EXTERNAL METRIC THREAD DIMENSIONS CHART


Metric thread dimensions chart for external threads according to ASME B1.13M-2005 "Metric Screw Threads: M Profile" standard. Dimensions of major diameter, pitch diameter and minor diameter for M profile metric external threads are given in the chart. All dimensions are in millimeters.

External thread (or bolt thread) is a term to describe all external threads in ISO metric thread standards.

Threads produced to ASME B1.13M-2005 standard are fully interchangeable with threads that are based on ISO 68-1 basic profile and ISO 965-1 tolerance practices.

External Thread Tolerance Classes:

    - for normal tolerance — tolerance class 6g

    - for tighter tolerance — tolerance class 4g6g

    - for a no-allowance fit at maximum material, such as for a plated 6g — tolerance class 6h

Size limits for standard external thread tolerance classes 6g and 4g6g apply prior to coating. The external thread allowance may thus be used to accommodate the coating thickness on coated parts.

The designation of a screw thread gives the thread symbol, the nominal size, the pitch, and the thread tolerance class (Ex: M6 x 1 - 4g6g). In tolerance class designation, the pitch diameter tolerance is followed by major diameter tolerance. If the two class designations for the pitch diameter and major diameter are same, it is not necessary to repeat the symbols. (Ex: M6 x 1 - 6g)

External Thread M Profile With No Allowance

Metric Thread Calculator:

INPUT PARAMETERS
Thread Designation
Tolerance Class
 




RESULTS
Thread Designation ---
Pitch, p ---
Tolerance Class ---
Major Diameter dmax   ---
dmin ---
Pitch Diameter d2max ---
d2min ---
Maximum Minor Diameter (Flat Form) d1max ---
Maximum Minor Diameter (Rounded Form) d3max ---
Minimum Minor Diameter (Rounded Form) d3min ---

General Note: All dimensions are in millimeters.

Note-1: Maximum rounded form minor diameter is calculated with following formula. The rest of the dimensions are tabulated values from the ASME standard.

Maximum rounded form minor diameter = d3max =  d2max - (0.5H + 2rmin (1 − cos (60deg − arccos(1 − Td2/ 4rmin)))). Here, rmin is minimum root radius, Td2 is pitch diameter tolerance and H is height of sharp V-thread.

Metric Thread Chart:

External Metric Thread Chart — Limiting Dimensions for M Profile
Thread
Designation
Pitch, p Tolerance
Class
Major Dia.,
d
Pitch Dia.,
d2
Max.
Minor
Diameter
(Flat
Form)
d1
Min.
Minor
Diameter
(Rounded
Form)
d3
max. min. max. min.
M1.6 x 0.35 0.35 6g 1.581 1.496 1.354 1.291 1.202 1.075
M1.6 x 0.35 0.35 6h 1.600 1.515 1.373 1.310 1.221 1.094
M1.6 x 0.35 0.35 4g6g 1.581 1.496 1.354 1.314 1.202 1.098
M2 x 0.4 0.4 6g 1.981 1.886 1.721 1.654 1.548 1.408
M2 x 0.4 0.4 6h 2.000 1.905 1.740 1.673 1.567 1.427
M2 x 0.4 0.4 4g6g 1.981 1.886 1.721 1.679 1.548 1.433
M2.5 x 0.45 0.45 6g 2.480 2.380 2.188 2.117 1.993 1.840
M2.5 x 0.45 0.45 6h 2.500 2.400 2.208 2.137 2.013 1.860
M2.5 x 0.45 0.45 4g6g 2.480 2.380 2.188 2.143 1.993 1.866
M3 x 0.5 0.5 6g 2.980 2.874 2.655 2.580 2.438 2.272
M3 x 0.5 0.5 6h 3.000 2.894 2.675 2.600 2.458 2.292
M3 x 0.5 0.5 4g6g 2.980 2.874 2.655 2.607 2.438 2.299
M3.5 x 0.6 0.6 6g 3.479 3.354 3.089 3.004 2.829 2.634
M3.5 x 0.6 0.6 6h 3.500 3.375 3.110 3.025 2.850 2.655
M3.5 x  0.6 0.6 4g6g 3.479 3.354 3.089 3.036 2.829 2.666
M4 x 0.7 0.7 6g 3.978 3.838 3.523 3.433 3.220 3.002
M4 x 0.7 0.7 6h 4.000 3.860 3.545 3.455 3.242 3.024
M4 x 0.7 0.7 4g6g 3.978 3.838 3.523 3.467 3.220 3.036
M5 x 0.8 0.8 6g 4.976 4.826 4.456 4.361 4.110 3.868
M5 x 0.8 0.8 6h 5.000 4.850 4.480 4.385 4.134 3.892
M5 x 0.8 0.8 4g6g 4.976 4.826 4.456 4.396 4.110 3.903
M6 x 1 1 6g 5.974 5.794 5.324 5.212 4.891 4.596
M6 x 1 1 6h 6.000 5.820 5.350 5.238 4.917 4.622
M6 x 1 1 4g6g 5.974 5.794 5.324 5.253 4.891 4.637
M8 x 1.25 1.25 6g 7.972 7.760 7.160 7.042 6.619 6.272
M8 x 1.25 1.25 6h 8.000 7.788 7.188 7.070 6.647 6.300
M8 x 1.25 1.25 4g6g 7.972 7.760 7.160 7.085 6.619 6.315
M8 x 1 1 6g 7.974 7.794 7.324 7.212 6.891 6.596
M8 x 1 1 6h 8.000 7.820 7.350 7.238 6.917 6.622
M8 x 1 1 4g6g 7.974 7.794 7.324 7.253 6.891 6.637
M10 x 1.5 1.5 6g 9.968 9.732 8.994 8.862 8.344 7.938
M10 x 1.5 1.5 6h 10.000 9.764 9.026 8.894 8.376 7.970
M10 x 1.5 1.5 4g6g 9.968 9.732 8.994 8.909 8.344 7.985
M10 x 1.25 1.25 6g 9.972 9.760 9.160 9.042 8.619 8.272
M10 x 1.25 1.25 6h 10.000 9.788 9.188 9.070 8.647 8.300
M10 x 1.25 1.25 4g6g 9.972 9.760 9.160 9.085 8.619 8.315
M10 x 1 1 6g 9.974 9.794 9.324 9.212 8.891 8.596
M10 x 1 1 6h 10.000 9.820 9.350 9.238 8.917 8.622
M10 x 1 1 4g6g 9.974 9.794 9.324 9.253 8.891 8.637
M10 x 0.75 0.75 6g 9.978 9.838 9.491 9.391 9.166 8.929
M10 x 0.75 0.75 6h 10.000 9.860 9.513 9.413 9.188 8.951
M10 x 0.75 0.75 4g6g 9.978 9.838 9.491 9.428 9.166 8.966
M12 x 1.75 1.75 6g 11.966 11.701 10.829 10.679 10.071 9.601
M12 x 1.75 1.75 6h 12.000 11.735 10.863 10.713 10.105 9.635
M12 x 1.75 1.75 4g6g 11.966 11.701 10.829 10.734 10.071 9.656
M12 x 1.5 1.5 6g 11.968 11.732 10.994 10.854 10.344 9.930
M12 x 1.5 1.5 6h 12.000 11.764 11.026 10.886 10.376 9.962
M12 x 1.5 1.5 4g6g 11.968 11.732 10.994 10.904 10.344 9.980
M12 x 1.25 1.25 6g 11.972 11.760 11.160 11.028 10.619 10.258
M12 x 1.25 1.25 6h 12.000 11.788 11.188 11.056 10.647 10.286
M12 x 1.25 1.25 4g6g 11.972 11.760 11.160 11.075 10.619 10.305
M12 x 1 1 6g 11.974 11.794 11.324 11.206 10.891 10.590
M12 x 1 1 6h 12.000 11.820 11.350 11.232 10.917 10.616
M12 x 1 1 4g6g 11.974 11.794 11.324 11.249 10.891 10.633
M14 x 2 2 6g 13.962 13.682 12.663 12.503 11.797 11.271
M14 x 2 2 6h 14.000 13.720 12.701 12.541 11.835 11.309
M14 x 2 2 4g6g 13.962 13.682 12.663 12.563 11.797 11.331
M14 x 1.5 1.5 6g 13.968 13.732 12.994 12.854 12.344 11.930
M14 x 1.5 1.5 6h 14.000 13.764 13.026 12.886 12.376 11.962
M14 x 1.5 1.5 4g6g 13.968 13.732 12.994 12.904 12.344 11.980
M15 x 1 1 6g 14.974 14.794 14.324 14.206 13.891 13.590
M15 x 1 1 6h 15.000 14.820 14.350 14.232 13.917 13.616
M15 x 1 1 4g6g 14.974 14.794 14.324 14.249 13.891 13.633
M16 x 2 2 6g 15.962 15.682 14.663 14.503 13.797 13.271
M16 x 2 2 6h 16.000 15.720 14.701 14.541 13.835 13.309
M16 x 2 2 4g6g 15.962 15.682 14.663 14.563 13.797 13.331
M16 x 1.5 1.5 6g 15.968 15.732 14.994 14.854 14.344 13.930
M16 x 1.5 1.5 6h 16.000 15.764 15.026 14.886 14.376 13.962
M16 x 1.5 1.5 4g6g 15.968 15.732 14.994 14.904 14.344 13.980
M17 x 1 1 6g 16.974 16.794 16.324 16.206 15.891 15.590
M17 x 1 1 6h 17.000 16.820 16.350 16.232 15.917 15.616
M17 x 1 1 4g6g 16.974 16.794 16.324 16.249 15.891 15.633
M18 x 1.5  1.5 6g 17.968 17.732 16.994 16.854 16.344 15.930
M18 x 1.5  1.5 6h 18.000 17.764 17.026 16.886 16.376 15.962
M18 x 1.5  1.5 4g6g 17.968 17.732 16.994 16.904 16.344 15.980
M20 x 2.5 2.5 6g 19.958 19.623 18.334 18.164 17.251 16.624
M20 x 2.5 2.5 6h 20.000 19.665 18.376 18.206 17.293 16.666
M20 x 2.5 2.5 4g6g 19.958 19.623 18.334 18.228 17.251 16.688
M20 x 1.5 1.5 6g 19.968 19.732 18.994 18.854 18.344 17.930
M20 x 1.5 1.5 6h 20.000 19.764 19.026 18.886 18.376 17.962
M20 x 1.5 1.5 4g6g 19.968 19.732 18.994 18.904 18.344 17.980
M20 x 1 1 6g 19.974 19.794 19.324 19.206 18.891 18.590
M20 x 1 1 6h 20.000 19.820 19.350 19.232 18.917 18.616
M20 x 1 1 4g6g 19.974 19.794 19.324 19.249 18.891 18.633
M22 x 2.5 2.5 6g 21.958 21.623 20.334 20.164 19.251 18.624
M22 x 2.5 2.5 6h 22.000 21.665 20.376 20.206 19.293 18.666
M22 x 1.5 1.5 6g 21.968 21.732 20.994 20.854 20.344 19.930
M22 x 1.5 1.5 6h 22.000 21.764 21.026 20.886 20.376 19.962
M22 x 1.5 1.5 4g6g 21.968 21.732 20.994 20.904 20.344 19.980
M24 x 3 3 6g 23.952 23.577 22.003 21.803 20.704 19.955
M24 x 3 3 6h 24.000 23.625 22.051 21.851 20.752 20.003
M24 x 3 3 4g6g 23.952 23.577 22.003 21.878 20.704 20.030
M24 x 2 2 6g 23.962 23.682 22.663 22.493 21.797 21.261
M24 x 2 2 6h 24.000 23.720 22.701 22.531 21.835 21.299
M24 x 2 2 4g6g 23.962 23.682 22.663 22.557 21.797 21.325
M25 x 1.5 1.5 6g 24.968 24.732 23.994 23.844 23.344 22.920
M25 x 1.5 1.5 6h 25.000 24.764 24.026 23.876 23.376 22.952
M25 x 1.5 1.5 4g6g 24.968 24.732 23.994 23.899 23.344 22.975
M27 x 3 3 6g 26.952 26.577 25.003 24.803 23.704 22.955
M27 x 3 3 6h 27.000 26.625 25.051 24.851 23.752 23.003
M27 x 2 2 6g 26.962 26.682 25.663 25.493 24.797 24.261
M27 x 2 2 6h 27.000 26.720 25.701 25.531 24.835 24.299
M27 x 2 2 4g6g 26.962 26.682 25.663 25.557 24.797 24.325
M30 x 3.5 3.5 6g 29.947 29.522 27.674 27.462 26.158 25.306
M30 x 3.5 3.5 6h 30.000 29.575 27.727 27.515 26.211 25.359
M30 x 3.5 3.5 4g6g 29.947 29.522 27.674 27.542 26.158 25.386
M30 x 2 2 6g 29.962 29.682 28.663 28.493 27.797 27.261
M30 x 2 2 6h 30.000 29.720 28.701 28.531 27.835 27.299
M30 x 2 2 4g6g 29.962 29.682 28.663 28.557 27.797 27.325
M30 x 1.5 1.5 6g 29.968 29.732 28.994 28.844 28.344 27.920
M30 x 1.5 1.5 6h 30.000 29.764 29.026 28.876 28.376 27.952
M30 x 1.5 1.5 4g6g 29.968 29.732 28.994 28.899 28.344 27.975
M33 x 2 2 6g 32.962 32.682 31.663 31.493 30.797 30.261
M33 x 2 2 6h 33.000 32.720 31.701 31.531 30.835 30.299
M33 x 2 2 4g6g 32.962 32.682 31.663 31.557 30.797 30.325
M35 x 1.5 1.5 6g 34.968 34.732 33.994 33.844 33.344 32.920
M35 x 1.5 1.5 6h 35.000 34.764 34.026 33.876 33.376 32.952
M36 x 4 4 6g 35.940 35.465 33.342 33.118 31.610 30.654
M36 x 4 4 6h 36.000 35.525 33.402 33.178 31.670 30.714
M36 x 4 4 4g6g 35.940 35.465 33.342 33.202 31.610 30.738
M36 x 2 2 6g 35.962 35.682 34.663 34.493 33.797 33.261
M36 x 2 2 6h 36.000 35.720 34.701 34.531 33.835 33.299
M36 x 2 2 4g6g 35.962 35.682 34.663 34.557 33.797 33.325
M39 x 2 2 6g 38.962 38.682 37.663 37.493 36.797 36.261
M39 x 2 2 6h 39.000 38.720 37.701 37.531 36.835 36.299
M39 x 2 2 4g6g 38.962 38.682 37.663 37.557 36.797 36.325
M40 x 1.5 1.5 6g 39.968 39.732 38.994 38.844 38.344 37.920
M40 x 1.5 1.5 6h 40.000 39.764 39.026 38.876 38.376 37.952
M40 x 1.5 1.5 4g6g 39.968 39.732 38.994 38.899 38.344 37.975

General Note: All dimensions are in millimeters.

Supplements:

Link Usage
ISO metric screw thread calculator ISO metric screw thread calculator based on ISO standards
Internal Metric Thread Chart Internal metric thread chart according to ASME B1.13M-2005 standard.

Definitions:

Allowance: The difference between the maximum material size and the basic size.

Basic profile: The theoretical profile of a screw thread in an axial plane defined by theoretical dimensions and angles common to internal and external threads. The basic M thread profile for metric screw threads is shown below.

The basic profile for ISO general purpose metric screw threads

ISO metric screw thread basic profile according to ISO 68-1

Reference:

  • ASME B1.13M-2005 "Metric Screw Threads: M Profile"
  • Oberg, E. , Jones ,F.D. , Horton H.L. , Ryffel H.H., (2016) . Machinery's Handbook . 30th edition.  Industrial Press Inc.
  • Oberg, E. , Jones ,F.D. , Horton H.L. , Ryffel H.H., (2012) . Machinery's Handbook . 29th edition.  Industrial Press Inc.