ISO 724:2023

ISO general purpose metric screw threads — Basic dimensions

This document specifies the basic dimensions of ISO general purpose metric screw threads according to ISO 261. The values refer to the design profiles according to ISO 68-1. This document is applicable to the metric fastening screw threads.

Filetages métriques ISO pour usages généraux — Dimensions de base

Le présent document spécifie les dimensions de base des filetages métriques ISO pour usages généraux conformément à l'ISO 261. Les valeurs se réfèrent aux profils nominaux conformément à l'ISO 68-1. Le présent document s'applique aux filetages métriques pour les fixations.

General Information

• Status: Published
• Publication Date: 20-Apr-2023
• ICS: 21.040.10 - Metric screw threads
• Technical Committee: ISO/TC 1 - Screw threads
• Drafting Committee: ISO/TC 1 - Screw threads
• Current Stage: 6060 - International Standard published
• Start Date: 21-Apr-2023
• Due Date: 23-May-2024
• Completion Date: 21-Apr-2023

Relations

• Revises: ISO 724:1993 - ISO general-purpose metric screw threads — Basic dimensions
• Effective Date: 06-Jun-2022

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 724
Third edition
2023-04
ISO general purpose metric screw
threads — Basic dimensions
Filetages métriques ISO pour usages généraux — Dimensions de base
Reference number
ISO 724:2023(E)
© ISO 2023

---------------------- Page: 1 ----------------------
ISO 724:2023(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
  © ISO 2023 – All rights reserved

---------------------- Page: 2 ----------------------
ISO 724:2023(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 1
5 Basic dimensions . 2
Bibliography .12
iii
© ISO 2023 – All rights reserved

---------------------- Page: 3 ----------------------
ISO 724:2023(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 1, Screw threads.
This third edition cancels and replaces the second edition (ISO 724:1993), which has been technically
revised. It also incorporates the Technical Corrigendum ISO 724:1993/Cor 1:2009.
The main changes are as follows:
— “basic profile” has been replaced with “design profile” in the Scope;
— a second paragraph has been added in the Scope;
— three symbols, d , H and h , have been added in Clause 4;
3 1 3
— the values and formula for the minor diameter of external thread, d , have been added in Table 1 and
3
Clause 5;
— ISO 68-1 and ISO 261 have been added in the Bibliography.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
  © ISO 2023 – All rights reserved

---------------------- Page: 4 ----------------------
INTERNATIONAL STANDARD ISO 724:2023(E)
ISO general purpose metric screw threads — Basic
dimensions
1 Scope
This document specifies the basic dimensions of ISO general purpose metric screw threads according
to ISO 261. The values refer to the design profiles according to ISO 68-1.
This document is applicable to the metric fastening screw threads.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 5408, Screw threads — Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 5408 apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
4 Symbols
For the purposes of this document, the following symbols apply.
D major diameter of internal thread (nominal diameter)
d major diameter of external thread (nominal diameter)
D pitch diameter of internal thread
2
d pitch diameter of external thread
2
D minor diameter of internal thread
1
d minor diameter of external thread on design profile
3
P pitch
H fundamental triangle height
H thread height of internal thread on design profile
1
h thread height of external thread on design profile
3
1
© ISO 2023 – All rights reserved

---------------------- Page: 5 ----------------------
ISO 724:2023(E)
5 Basic dimensions
Basic dimensions shown in Figure 1 are given in Table 1.
The values of D , d , D and d , in Table 1, have been calculated from the following formulae and rounded
2 2 1 3
to the third decimal place.
D = d = d – 2 × 3H/8 = d – 0,649 519 P
2 2
D = d – 2 × H = d – 1,082 532 P
1 1
d = d – 2 × h = d – 1,226 869 P
3 3
Key
1 internal thread
2 external thread
Figure 1 — Basic dimensions on design profiles
Table 1 — Basic dimensions
Dimensions in millimetres
Minor diameter
Nominal diameter,
Internal thread External thread
Pitch Pitch diameter
major diameter
flat crest rounded root
D, d P D , d D d
2 2 1 3
0,2 0,870 0,783 0,755
1
0,25 0,838 0,729 0,693
0,2 0,970 0,883 0,855
1,1
0,25 0,938 0,829 0,793
0,2 1,070 0,983 0,955
1,2
0,25 1,038 0,929 0,893
0,2 1,270 1,183 1,155
1,4
0,3 1,205 1,075 1,032
2
  © ISO 2023 – All rights reserved

---------------------- Page: 6 ----------------------
ISO 724:2023(E)
TTabablele 1 1 ((ccoonnttiinnueuedd))
Minor diameter
Nominal diameter,
Internal thread External thread
Pitch Pitch diameter
major diameter
flat crest rounded root
D, d P D , d D d
2 2 1 3
0,2 1,470 1,383 1,355
1,6
0,35 1,373 1,221 1,171
0,2 1,670 1,583 1,555
1,8
0,35 1,573 1,421 1,371
0,25 1,838 1,729 1,693
2
0,4 1,740 1,567 1,509
0,25 2,038 1,929 1,893
2,2
0,45 1,908 1,713 1,648
0,35 2,273 2,121 2,071
2,5
0,45 2,208 2,013 1,948
0,35 2,773 2,621 2,571
3
0,5 2,675 2,459 2,387
0,35 3,273 3,121 3,071
3,5
0,6 3,110 2,850 2,764
0,5 3,675 3,459 3,387
4
0,7 3,545 3,242 3,141
0,5 4,175 3,959 3,887
4,5
0,75 4,013 3,688 3,580
0,5 4,675 4,459 4,387
5
0,8 4,480 4,134 4,019
5,5 0,5 5,175 4,959 4,887
0,75 5,513 5,188 5,080
6
1 5,350 4,917 4,773
0,75 6,513 6,188 6,080
7
1 6,350 5,917 5,773
0,75 7,513 7,188 7,080
8 1 7,350 6,917 6,773
1,25 7,188 6,647 6,466
0,75 8,513 8,188 8,080
9 1 8,350 7,917 7,773
1,25 8,188 7,647 7,466
0,75 9,513 9,188 9,080
1 9,350 8,917 8,773
10
1,25 9,188 8,647 8,466
1,5 9,026 8,376 8,160
0,75 10,513 10,188 10,080
11 1 10,350 9,917 9,773
1,5 10,026 9,376 9,160
3
© ISO 2023 – All rights reserved

---------------------- Page: 7 ----------------------
ISO 724:2023(E)
TTabablele 1 1 ((ccoonnttiinnueuedd))
Minor diameter
Nominal diameter,
Internal thread External thread
Pitch Pitch diameter
major diameter
flat crest rounded root
D, d P D , d D d
2 2 1 3
1 11,350 10,917 10,773
1,25 11,188 10,647 10,466
12
1,5 11,026 10,376 10,160
1,75 10,863 10,106 9,853
1 13,350 12,917 12,773
14 1,5 13,026 12,376 12,160
2 12,701 11,835 11,546
1 14,350 13,917 13,773
15
1,5 14,026 13,376 13,160
1 15,350 14,917 14,773
16 1,5 15,026 14,376 14,160
2 14,701 13,835 13,546
1 16,350 15,917 15,773
17
1,5 16,026 15,376 15,160
1 17,350 16,917 16,773
1,5 17,026 16,376 16,160
18
2 16,701 15,835 15,546
2,5 16,376 15,294 1
...

NORME ISO
INTERNATIONALE 724
Troisième édition
2023-04
Filetages métriques ISO pour usages
généraux — Dimensions de base
ISO general purpose metric screw threads — Basic dimensions
Numéro de référence
ISO 724:2023(F)
© ISO 2023

---------------------- Page: 1 ----------------------
ISO 724:2023(F)
DOCUMENT PROTÉGÉ PAR COPYRIGHT
© ISO 2023
Tous droits réservés. Sauf prescription différente ou nécessité dans le contexte de sa mise en œuvre, aucune partie de cette
publication ne peut être reproduite ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique,
y compris la photocopie, ou la diffusion sur l’internet ou sur un intranet, sans autorisation écrite préalable. Une autorisation peut
être demandée à l’ISO à l’adresse ci-après ou au comité membre de l’ISO dans le pays du demandeur.
ISO copyright office
Case postale 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Genève
Tél.: [phone]
E-mail: [e-mail]
Web: www.iso.org
Publié en Suisse
ii
  © ISO 2023 – Tous droits réservés

---------------------- Page: 2 ----------------------
ISO 724:2023(F)
Sommaire Page
Avant-propos .iv
1 Domaine d'application .1
2 Références normatives .1
3 Termes et définitions . 1
4 Symboles . 1
5 Dimensions de base . 2
Bibliographie .12
iii
© ISO 2023 – Tous droits réservés

---------------------- Page: 3 ----------------------
ISO 724:2023(F)
Avant-propos
L'ISO (Organisation internationale de normalisation) est une fédération mondiale d'organismes
nationaux de normalisation (comités membres de l'ISO). L'élaboration des Normes internationales est
en général confiée aux comités techniques de l'ISO. Chaque comité membre intéressé par une étude
a le droit de faire partie du comité technique créé à cet effet. Les organisations internationales,
gouvernementales et non gouvernementales, en liaison avec l'ISO participent également aux travaux.
L'ISO collabore étroitement avec la Commission électrotechnique internationale (IEC) en ce qui
concerne la normalisation électrotechnique.
Les procédures utilisées pour élaborer le présent document et celles destinées à sa mise à jour sont
décrites dans les Directives ISO/IEC, Partie 1. Il convient, en particulier de prendre note des différents
critères d'approbation requis pour les différents types de documents ISO. Le présent document
a été rédigé conformément aux règles de rédaction données dans les Directives ISO/IEC, Partie 2
(voir www.iso.org/directives).
L'attention est attirée sur le fait que certains des éléments du présent document peuvent faire l'objet de
droits de propriété intellectuelle ou de droits analogues. L'ISO ne saurait être tenue pour responsable
de ne pas avoir identifié de tels droits de propriété et averti de leur existence. Les détails concernant
les références aux droits de propriété intellectuelle ou autres droits analogues identifiés lors de
l'élaboration du document sont indiqués dans l'Introduction et/ou dans la liste des déclarations de
brevets reçues par l'ISO (voir www.iso.org/brevets).
Les appellations commerciales éventuellement mentionnées dans le présent document sont données
pour information, par souci de commodité, à l’intention des utilisateurs et ne sauraient constituer un
engagement.
Pour une explication de la nature volontaire des normes, la signification des termes et expressions
spécifiques de l'ISO liés à l'évaluation de la conformité, ou pour toute information au sujet de l'adhésion
de l'ISO aux principes de l’Organisation mondiale du commerce (OMC) concernant les obstacles
techniques au commerce (OTC), voir www.iso.org/avant-propos.
Le présent document a été élaboré par le comité technique ISO/TC 1, Filetages.
Cette troisième édition annule et remplace la deuxième édition (ISO 724:1993), qui a fait l'objet d'une
révision technique. Elle incorpore également le Rectificatif technique ISO 724:1993/Cor.1:2009.
Les principales modifications sont les suivantes:
— “profil de base” a été remplacé par “profil nominal” dans le Domaine d'application;
— un second alinéa a été ajouté dans le Domaine d'application;
— trois symboles, d , H et h , ont été ajoutés dans l'Article 4;
3 1 3
— les valeurs et formules pour le diamètre intérieur du filetage extérieur, d , ont été ajoutées dans le
3
Tableau 1 et dans l'Article 5;
— l'ISO 68-1 et l'ISO 261 ont été ajoutées en Bibliographie.
Il convient que l’utilisateur adresse tout retour d’information ou toute question concernant le présent
document à l’organisme national de normalisation de son pays. Une liste exhaustive desdits organismes
se trouve à l’adresse www.iso.org/fr/members.html.
iv
  © ISO 2023 – Tous droits réservés

---------------------- Page: 4 ----------------------
NORME INTERNATIONALE ISO 724:2023(F)
Filetages métriques ISO pour usages généraux —
Dimensions de base
1 Domaine d'application
Le présent document spécifie les dimensions de base des filetages métriques ISO pour usages généraux
conformément à l'ISO 261. Les valeurs se réfèrent aux profils nominaux conformément à l'ISO 68-1.
Le présent document s'applique aux filetages métriques pour les fixations.
2 Références normatives
Les documents suivants sont cités dans le texte de sorte qu’ils constituent, pour tout ou partie de leur
contenu, des exigences du présent document. Pour les références datées, seule l’édition citée s’applique.
Pour les références non datées, la dernière édition du document de référence s'applique (y compris les
éventuels amendements).
ISO 5408, Filetages — Vocabulaire
3 Termes et définitions
Pour les besoins du présent document, les termes et définitions donnés dans l'ISO 5408 s'appliquent.
L'ISO et l'IEC tiennent à jour des bases de données terminologiques destinées à être utilisées en
normalisation, consultables aux adresses suivantes:
— ISO Online browsing platform: disponible à l'adresse https:// www .iso .org/ obp
— IEC Electropedia: disponible à l'adresse https:// www .electropedia .org/
4 Symboles
Pour les besoins du présent document, les symboles suivants s'appliquent.
D diamètre extérieur du filetage intérieur (diamètre nominal)
d diamètre extérieur du filetage extérieur (diamètre nominal)
D diamètre sur flancs du filetage intérieur
2
d diamètre sur flancs du filetage extérieur
2
D diamètre intérieur du filetage intérieur
1
d diamètre intérieur du filetage extérieur sur profil nominal
3
P pas du profil
H hauteur du triangle générateur
H hauteur de filetage du filetage intérieur sur profil nominal
1
h hauteur de filetage du filetage extérieur sur profil nominal
3
1
© ISO 2023 – Tous droits réservés

---------------------- Page: 5 ----------------------
ISO 724:2023(F)
5 Dimensions de base
Les dimensions de base montrées dans la Figure 1 sont données dans le Tableau 1.
Les valeurs de D , d , D et d , dans le Tableau 1, ont été calculées à partir des formules suivantes et
2 2 1 3
arrondies à la troisième décimale.
D = d = d – 2 × 3H/8 = d – 0,649 519 P
2 2
D = d – 2 × H = d – 1,082 532 P
1 1
d = d – 2 × h = d – 1,226 869 P
3 3
Légende
1 filetage intérieur
2 filetage extérieur
Figure 1 — Dimensions de base sur profils nominaux
Tableau 1 — Dimensions de base
Dimensions en millimètres
Diamètre intérieur
Diamètre nomi-
nal,
Filetage inté- Filetage exté-
Diamètre sur
Pas
rieur rieur
flancs
diamètre exté-
rieur
sommet plat fond arrondi
D, d P D , d D d
2 2 1 3
0,2 0,870 0,783 0,755
1
0,25 0,838 0,729 0,693
0,2 0,970 0,883 0,855
1,1
0,25 0,938 0,829 0,793
0,2 1,070 0,983 0,955
1,2
0,25 1,038 0,929 0,893
0,2 1,270 1,183 1,155
1,4
0,3 1,205 1,075 1,032
2
  © ISO 2023 – Tous droits réservés

---------------------- Page: 6 ----------------------
ISO 724:2023(F)
TTabableleaauu 1 1 ((ssuuiitte)e)
Diamètre intérieur
Diamètre nomi-
nal,
Filetage inté- Filetage exté-
Diamètre sur
Pas
rieur rieur
flancs
diamètre exté-
rieur
sommet plat fond arrondi
D, d P D , d D d
2 2 1 3
0,2 1,470 1,383 1,355
1,6
0,35 1,373 1,221 1,171
0,2 1,670 1,583 1,555
1,8
0,35 1,573 1,421 1,371
0,25 1,838 1,729 1,693
2
0,4 1,740 1,567 1,509
0,25 2,038 1,929 1,893
2,2
0,45 1,908 1,713 1,648
0,35 2,273 2,121 2,071
2,5
0,45 2,208 2,013 1,948
0,35 2,773 2,621 2,571
3
0,5 2,675 2,459 2,387
0,35 3,273 3,121 3,071
3,5
0,6 3,110 2,850 2,764
0,5 3,675 3,459 3,387
4
0,7 3,545 3,242 3,141
0,5 4,175 3,959 3,887
4,5
0,75 4,013 3,688 3,580
0,5 4,675 4,459 4,387
5
0,8 4,480 4,134 4,019
5,5 0,5 5,175 4,959 4,887
0,75 5,513 5,188 5,080
6
1 5,350 4,917 4,773
0,75 6,513 6,188 6,080
7
1 6,350 5,917 5,773
0,75 7,513 7,188 7,080
8 1 7,350 6,917 6,773
1,25 7,188 6,647 6,466
0,75 8,513 8,188 8,080
9 1 8,350 7,917 7,773
1,25 8,188 7,647 7,466
0,75 9,513 9,188 9,080
1 9,350 8,917 8,773
10
1,25 9,188 8,647 8,466
1,5 9,026 8,376 8,160
0,75 10,513 10,188 10,080
11 1 10,350 9,917 9,773
1,5 10,026 9,376 9,160
3
© ISO 2023 – Tous droits réservés

---------------------- Page: 7 ----------------------
ISO 724:2023(F)
TTabableleaauu 1 1 ((ssuuiitte)e)
Diamètre intérieur
Diamètre nomi-
nal,
Filetage inté- Filetage exté-
Diamètre sur
Pas
rieur rieur
flancs
diamètre exté-
rieur
sommet plat fond arrondi
D, d P D , d D d
2 2 1 3
1 11,350 10,917 10,773
1,25 11,188 10,647 10,466
12
1,5 11,026 10,376
...

ISO /PRF 724:2023(E)
ISO /TC 1
Date: 2022-12-29
Secretariat: SAC

Date: 2023-02-22
ISO general purpose metric screw threads — Basic dimensions
Filetages métriques ISO pour usages généraux — Dimensions de base
FDIS stage

---------------------- Page: 1 ----------------------
ISO /PRF 724:2023(E)
© ISO 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this
publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical,
including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can
be requested from either ISO at the address below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: + 41 22 749 01 11
EmailE-mail: [e-mail]
Website: www.iso.orgwww.iso.org
Published in Switzerland
ii © ISO 2023 – All rights reserved
ii © ISO 2023 – All rights reserved

---------------------- Page: 2 ----------------------
ISO /PRF 724:2023(E)
Contents
Foreword . iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 1
5 Basic dimensions . 1
Bibliography . 13

© ISO 2023 – All rights reserved iii
© ISO 2023 – All rights reserved iii

---------------------- Page: 3 ----------------------
ISO /PRF 724:2023(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO
collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Field Code Changed
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any
patent rights identified during the development of the document will be in the Introduction and/or on
the ISO list of patent declarations received (see www.iso.org/patentswww.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the World
Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.htmlwww.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 1, Screw threads.
This third edition cancels and replaces the second edition (ISO 724:1993, including Cor 1:2009), which
has been technically revised.
The main changes are as follows:
— — “basic profile” has been replaced with “design profile” in the Scope;
— — a second paragraph has been added in the Scope;
— — three symbols, d , H and h , have been added in Clause 4;Clause 4;
3 1 3
— — the values and formula for the minor diameter of external thread, d , have been added in
3
Table 1Table 1 and Clause 5;Clause 5;
— — ISO 68-1 and ISO 261 have been added in the Bibliography.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
Field Code Changed
iv © ISO 2023 – All rights reserved
iv © ISO 2023 – All rights reserved

---------------------- Page: 4 ----------------------
INTERNATIONAL STANDARD ISO 724:2023(E)

ISO general purpose metric screw threads — Basic dimensions
1 Scope
This document specifies the basic dimensions of ISO general purpose metric screw threads according to
ISO 261. The values refer to the design profiles according to ISO 68-1.
This document is applicable to the metric fastening screw threads.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 5408, Screw threads — Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 5408 apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— — ISO Online browsing platform: available at https://www.iso.org/obphttps://www.iso.org/obp
— — IEC Electropedia: available at https://www.electropedia.org/https://www.electropedia.org/
4 Symbols
For the purposes of this document, the following symbols apply.
D major diameter of internal thread (nominal diameter)
d major diameter of external thread (nominal diameter)
D pitch diameter of internal thread
2
d pitch diameter of external thread
2
D minor diameter of internal thread
1
d minor diameter of external thread on design profile
3
P pitch
H fundamental triangle height
H1 thread height of internal thread on design profile
h thread height of external thread on design profile
3
5 Basic dimensions
Basic dimensions shown in Figure 1Figure 1 are given in Table 1.Table 1.
The values of D , d , D , and d , in Table 1,Table 1, have been calculated from the following formulae and
2 2 1 3
rounded to the third decimal place.
D = d = d – 2 × 3H/8 = d – 0,649 519 P
2 2
D = d – 2 × H = d – 1,082 532 P
1 1
d = d – 2 × h = d – 1,226 869 P
3 3
© ISO 2023 – All rights reserved 1

---------------------- Page: 5 ----------------------
ISO /PRF 724:2023(E)


Key
1 internal thread
2 external thread
Figure 1 — Basic dimensions on design profiles
Table 1 — Basic dimensions
Dimensions in millimetres
Minor diameter
Nominal diameter,
Pitch Pitch diameter
Internal thread External thread
major diameter
flat crest rounded root
D, d P D2, d2 D1 d3
0,2 0,870 0,783 0,755
1
0,25 0,838 0,729 0,693
0,2 0,970 0,883 0,855
1,1
0,25 0,938 0,829 0,793
0,2 1,070 0,983 0,955
1,2
0,25 1,038 0,929 0,893
1,4 0,2 1,270 1,183 1,155
2 © ISO 2023 – All rights reserved
2 © ISO 2023 – All rights reserved

---------------------- Page: 6 ----------------------
ISO /PRF 724:2023(E)
Minor diameter
Nominal diameter,
Pitch Pitch diameter
Internal thread External thread
major diameter
flat crest rounded root
D, d P D2, d2 D1 d3
0,3 1,205 1,075 1,032
0,2 1,470 1,383 1,355
1,6
0,35 1,373 1,221 1,171
0,2 1,670 1,583 1,555
1,8
0,35 1,573 1,421 1,371
0,25 1,838 1,729 1,693
2
0,4 1,740 1,567 1,509
0,25 2,038 1,929 1,893
2,2
0,45 1,908 1,713 1,648
0,35 2,273 2,121 2,071
2,5
0,45 2,208 2,013 1,948
0,35 2,773 2,621 2,571
3
0,5 2,675 2,459 2,387
0,35 3,273 3,121 3,071
3,5
0,6 3,110 2,850 2,764
0,5 3,675 3,459 3,387
4
0,7 3,545 3,242 3,141
0,5 4,175 3,959 3,887
4,5
0,75 4,013 3,688 3,580
0,5 4,675 4,459 4,387
5
0,8 4,480 4,134 4,019
5,5 0,5 5,175 4,959 4,887
0,75 5,513 5,188 5,080
6
1 5,350 4,917 4,773
0,75 6,513 6,188 6,080
7
1 6,350 5,917 5,773
0,75 7,513 7,188 7,080
8 1 7,350 6,917 6,773
1,25 7,188 6,647 6,466
0,75 8,513 8,188 8,080
9 1 8,350 7,917 7,773
1,25 8,188 7,647 7,466
0,75 9,513 9,188 9,080
1 9,350 8,917 8,773
10
1,25 9,188 8,647 8,466
1,5 9,026 8,376 8,160
© ISO 2023 – All rights reserved 3
© ISO 2023 – All rights reserved 3

---------------------- Page: 7 ----------------------
ISO /PRF 724:2023(E)
Minor diameter
Nominal diameter,
Pitch Pitch diameter
Internal thread External thread
major diameter
flat crest rounded root
D, d P D2, d2 D1 d3
0,75 10,513 10,188 10,080
11 1 10,350 9,917 9,773
1,5 10,026 9,376 9,160
1 11,350 10,917 10,773
1,25 11,188 10,647 10,466
12
1,5 11,026 10,376 10,160
1,75 10,863 10,106 9,853
1 13,350 12,917 12,773
14 1,5 13,026 12,376 12,160
2 12,701 11,835 11,546
1 14,350 13,917 13,773
15
1,5 14,026 13,376 13,160
1 15,350 14,917 14,773
16 1,5 15,026 14,376 14,160
2 14,701 13,835 13,546
1 16,350 15,917 15,773
17
1,5 16,026 15,376 15,160
1 17,350 16,917 16,773
1,5 17,026 16,376 16,160
18
2 16,701 15,835 15,546
2,5 16,376 15,294 14,933
1 19,350 18,917 18,773
1,5 19,026 18,376 18,160
20
2 18,701 17,835 17,546
2,5 18,376 17,294 16,933
1 21,350 20,917 20,773
1,5 21,026 20,376 20,160
22
2 20,701 19,835 19,546
2,5 20,376 19,294 18,93
...

INTERNATIONAL ISO
STANDARD 724
Third edition
ISO general purpose metric screw
threads — Basic dimensions
Filetages métriques ISO pour usages généraux — Dimensions de base
PROOF/ÉPREUVE
Reference number
ISO 724:2023(E)
© ISO 2023

---------------------- Page: 1 ----------------------
ISO 724:2023(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
PROOF/ÉPREUVE © ISO 2023 – All rights reserved

---------------------- Page: 2 ----------------------
ISO 724:2023(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 1
5 Basic dimensions . 2
Bibliography .12
iii
© ISO 2023 – All rights reserved PROOF/ÉPREUVE

---------------------- Page: 3 ----------------------
ISO 724:2023(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 1, Screw threads.
This third edition cancels and replaces the second edition (ISO 724:1993, including Cor 1:2009), which
has been technically revised.
The main changes are as follows:
— “basic profile” has been replaced with “design profile” in the Scope;
— a second paragraph has been added in the Scope;
— three symbols, d , H and h , have been added in Clause 4;
3 1 3
— the values and formula for the minor diameter of external thread, d , have been added in Table 1 and
3
Clause 5;
— ISO 68-1 and ISO 261 have been added in the Bibliography.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
PROOF/ÉPREUVE © ISO 2023 – All rights reserved

---------------------- Page: 4 ----------------------
INTERNATIONAL STANDARD ISO 724:2023(E)
ISO general purpose metric screw threads — Basic
dimensions
1 Scope
This document specifies the basic dimensions of ISO general purpose metric screw threads according
to ISO 261. The values refer to the design profiles according to ISO 68-1.
This document is applicable to the metric fastening screw threads.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 5408, Screw threads — Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 5408 apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
4 Symbols
For the purposes of this document, the following symbols apply.
D major diameter of internal thread (nominal diameter)
d major diameter of external thread (nominal diameter)
D pitch diameter of internal thread
2
d pitch diameter of external thread
2
D minor diameter of internal thread
1
d minor diameter of external thread on design profile
3
P pitch
H fundamental triangle height
H thread height of internal thread on design profile
1
h thread height of external thread on design profile
3
1
© ISO 2023 – All rights reserved PROOF/ÉPREUVE

---------------------- Page: 5 ----------------------
ISO 724:2023(E)
5 Basic dimensions
Basic dimensions shown in Figure 1 are given in Table 1.
The values of D , d , D and d , in Table 1, have been calculated from the following formulae and rounded
2 2 1 3
to the third decimal place.
D = d = d – 2 × 3H/8 = d – 0,649 519 P
2 2
D = d – 2 × H = d – 1,082 532 P
1 1
d = d – 2 × h = d – 1,226 869 P
3 3
Key
1 internal thread
2 external thread
Figure 1 — Basic dimensions on design profiles
Table 1 — Basic dimensions
Dimensions in millimetres
Minor diameter
Nominal diameter,
Internal thread External thread
Pitch Pitch diameter
major diameter
flat crest rounded root
D, d P D , d D d
2 2 1 3
0,2 0,870 0,783 0,755
1
0,25 0,838 0,729 0,693
0,2 0,970 0,883 0,855
1,1
0,25 0,938 0,829 0,793
0,2 1,070 0,983 0,955
1,2
0,25 1,038 0,929 0,893
0,2 1,270 1,183 1,155
1,4
0,3 1,205 1,075 1,032
2
PROOF/ÉPREUVE © ISO 2023 – All rights reserved

---------------------- Page: 6 ----------------------
ISO 724:2023(E)
TTabablele 1 1 ((ccoonnttiinnueuedd))
Minor diameter
Nominal diameter,
Internal thread External thread
Pitch Pitch diameter
major diameter
flat crest rounded root
D, d P D , d D d
2 2 1 3
0,2 1,470 1,383 1,355
1,6
0,35 1,373 1,221 1,171
0,2 1,670 1,583 1,555
1,8
0,35 1,573 1,421 1,371
0,25 1,838 1,729 1,693
2
0,4 1,740 1,567 1,509
0,25 2,038 1,929 1,893
2,2
0,45 1,908 1,713 1,648
0,35 2,273 2,121 2,071
2,5
0,45 2,208 2,013 1,948
0,35 2,773 2,621 2,571
3
0,5 2,675 2,459 2,387
0,35 3,273 3,121 3,071
3,5
0,6 3,110 2,850 2,764
0,5 3,675 3,459 3,387
4
0,7 3,545 3,242 3,141
0,5 4,175 3,959 3,887
4,5
0,75 4,013 3,688 3,580
0,5 4,675 4,459 4,387
5
0,8 4,480 4,134 4,019
5,5 0,5 5,175 4,959 4,887
0,75 5,513 5,188 5,080
6
1 5,350 4,917 4,773
0,75 6,513 6,188 6,080
7
1 6,350 5,917 5,773
0,75 7,513 7,188 7,080
8 1 7,350 6,917 6,773
1,25 7,188 6,647 6,466
0,75 8,513 8,188 8,080
9 1 8,350 7,917 7,773
1,25 8,188 7,647 7,466
0,75 9,513 9,188 9,080
1 9,350 8,917 8,773
10
1,25 9,188 8,647 8,466
1,5 9,026 8,376 8,160
0,75 10,513 10,188 10,080
11 1 10,350 9,917 9,773
1,5 10,026 9,376 9,160
3
© ISO 2023 – All rights reserved PROOF/ÉPREUVE

---------------------- Page: 7 ----------------------
ISO 724:2023(E)
TTabablele 1 1 ((ccoonnttiinnueuedd))
Minor diameter
Nominal diameter,
Internal thread External thread
Pitch Pitch diameter
major diameter
flat crest rounded root
D, d P D , d D d
2 2 1 3
1 11,350 10,917 10,773
1,25 11,188 10,647 10,466
12
1,5 11,026 10,376 10,160
1,75 10,863 10,106 9,853
1 13,350 12,917 12,773
14 1,5 13,026 12,376 12,160
2 12,701 11,835 11,546
1 14,350 13,917 13,773
15
1,5 14,026 13,376 13,160
1 15,350 14,917 14,773
16 1,5 15,026 14,376 14,160
2 14,701 13,835 13,546
1 16,350 15,917 15,773
17
1,5 16,026 15,376 15,160
1 17,350 16,917 16,773
1,5 17,026 16,376 16,160
18
2 16,701 15,835 15,546
2,5 16,376 15,294 14,933
1 19,350 18,917 18,773
1,5 19,026 18,376 1
...