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Metric Internal Thread Dimensions Chart

Metric internal thread dimensions chart according to ASME B1.13M "Metric Screw Threads: M Profile" standard. Minor diameter, pitch diameter and major diameter are given dimensions in the internal thread chart. All dimensions are in millimeters.

Internal thread (or nut thread) is a term to describe all internal threads in ISO metric thread standards.

Threads produced to ASME B1.13M standard are fully interchangeable with threads based on ISO 68-1 basic profile and ISO 965-1 tolerance practices. For mating sizes, see the Metric External Thread Chart.

Metric Internal Thread Calculator

Pick a designation — results update instantly from the chart table below.
Thread Designation Pitch, p Tolerance Class D1 min D1 max D2 min D2 max D min D max
— — — — — — — — —

General Note: All dimensions are in millimeters.

Metric Internal Thread Chart

Metric Internal Thread Chart — Limiting Dimensions for M Profile (ASME B1.13M)
Thread
Designation		 Pitch, p Tolerance
Class		 Minor Dia., D1 Pitch Dia., D2 Major Dia., D
min. max. min. max. min. max. (Note 1)
M1.6 x 0.35 0.35 6H 1.221 1.321 1.373 1.458 1.600 1.736
M2 x 0.4 0.4 6H 1.567 1.679 1.740 1.830 2.000 2.148
M2.5 x 0.45 0.45 6H 2.013 2.138 2.208 2.303 2.500 2.660
M3 x 0.5 0.5 6H 2.459 2.599 2.675 2.775 3.000 3.172
M3.5 x 0.6 0.6 6H 2.850 3.010 3.110 3.222 3.500 3.698
M4 x 0.7 0.7 6H 3.242 3.422 3.545 3.663 4.000 4.219
M5 x 0.8 0.8 6H 4.134 4.334 4.480 4.605 5.000 5.240
M6 x 1 1 6H 4.917 5.153 5.350 5.500 6.000 6.294
M8 x 1.25 1.25 6H 6.647 6.912 7.188 7.348 8.000 8.340
M8 x 1 1 6H 6.917 7.153 7.350 7.500 8.000 8.294
M10 x 1.5 1.5 6H 8.376 8.676 9.026 9.206 10.000 10.397
M10 x 1.25 1.25 6H 8.647 8.912 9.188 9.348 10.000 10.340
M10 x 1 1 6H 8.917 9.153 9.350 9.500 10.000 10.294
M10 x 0.75 0.75 6H 9.188 9.378 9.513 9.645 10.000 10.240
M12 x 1.75 1.75 6H 10.106 10.441 10.863 11.063 12.000 12.452
M12 x 1.5 1.5 6H 10.376 10.676 11.026 11.216 12.000 12.407
M12 x 1.25 1.25 6H 10.647 10.912 11.188 11.368 12.000 12.360
M12 x 1 1 6H 10.917 11.153 11.350 11.510 12.000 12.304
M14 x 2 2 6H 11.835 12.210 12.701 12.913 14.000 14.501
M14 x 1.5 1.5 6H 12.376 12.676 13.026 13.216 14.000 14.407
M15 x 1 1 6H 13.917 14.153 14.350 14.510 15.000 15.304
M16 x 2 2 6H 13.835 14.210 14.701 14.913 16.000 16.501
M16 x 1.5 1.5 6H 14.376 14.676 15.026 15.216 16.000 16.407
M17 x 1 1 6H 15.917 16.153 16.350 16.510 17.000 17.304
M18 x 1.5  1.5 6H 16.376 16.676 17.026 17.216 18.000 18.407
M20 x 2.5 2.5 6H 17.294 17.744 18.376 18.600 20.000 20.585
M20 x 1.5 1.5 6H 18.376 18.676 19.026 19.216 20.000 20.407
M20 x 1 1 6H 18.917 19.153 19.350 19.510 20.000 20.304
M22 x 2.5 2.5 6H 19.294 19.744 20.376 20.600 22.000 22.585
M22 x 1.5 1.5 6H 20.376 20.676 21.026 21.216 22.000 22.407
M24 x 3 3 6H 20.752 21.252 22.051 22.316 24.000 24.698
M24 x 2 2 6H 21.835 22.210 22.701 22.925 24.000 24.513
M25 x 1.5 1.5 6H 23.376 23.676 24.026 24.226 25.000 25.417
M27 x 3 3 6H 23.752 24.252 25.051 25.316 27.000 27.698
M27 x 2 2 6H 24.835 25.210 25.701 25.925 27.000 27.513
M30 x 3.5 3.5 6H 26.211 26.771 27.727 28.007 30.000 30.786
M30 x 2 2 6H 27.835 28.210 28.701 28.925 30.000 30.513
M30 x 1.5 1.5 6H 28.376 28.676 29.026 29.226 30.000 30.417
M33 x 2 2 6H 30.835 31.210 31.701 31.925 33.000 33.513
M35 x 1.5 1.5 6H 33.376 33.676 34.026 34.226 35.000 35.417
M36 x 4 4 6H 31.670 32.270 33.402 33.702 36.000 36.877
M36 x 2 2 6H 33.835 34.210 34.701 34.925 36.000 36.513
M39 x 2 2 6H 36.835 37.210 37.701 37.925 39.000 39.513
M40 x 1.5 1.5 6H 38.376 38.676 39.026 39.226 40.000 40.417
M42 x 4.5 4.5 6H 37.129 37.799 39.077 39.392 42.000 42.964
M42 x 2 2 6H 39.835 40.210 40.701 40.925 42.000 42.513
M45 x 1.5 1.5 6H 43.376 43.676 44.026 44.226 45.000 45.417
M48 x 5 5 6H 42.587 43.297 44.752 45.087 48.000 49.056
M48 x 2 2 6H 45.835 46.210 46.701 46.937 48.000 48.525
M50 x 1.5 1.5 6H 48.376 48.676 49.026 49.238 50.000 50.429
M55 x 1.5 1.5 6H 53.376 53.676 54.026 54.238 55.000 55.429
M56 x 5.5 5.5 6H 50.046 50.796 52.428 52.783 56.000 57.149
M56 x 2 2 6H 53.835 54.210 54.701 54.937 56.000 56.525
M60 x 1.5 1.5 6H 58.376 58.676 59.026 59.238 60.000 60.429
M64 x 6 6 6H 57.505 58.305 60.103 60.478 64.000 65.241
M64 x 2 2 6H 61.835 62.210 62.701 62.937 64.000 64.525
M65 x 1.5 1.5 6H 63.376 63.676 64.026 64.238 65.000 65.429
M70 x 1.5 1.5 6H 68.376 68.676 69.026 69.238 70.000 70.429
M72 x 6 6 6H 65.505 66.305 68.103 68.478 72.000 73.241
M72 x 2 2 6H 69.835 70.210 70.701 70.937 72.000 72.525
M75 x 1.5 1.5 6H 73.376 73.676 74.026 74.238 75.000 75.429
M80 x 6 6 6H 73.505 74.305 76.103 76.478 80.000 81.241
M80 x 2 2 6H 77.835 78.210 78.701 78.937 80.000 80.525
M80 x 1.5 1.5 6H 78.376 78.676 79.026 79.238 80.000 80.429
M85 x 2 2 6H 82.835 83.210 83.701 83.937 85.000 85.525
M90 x 6 6 6H 83.505 84.305 86.103 86.478 90.000 91.241
M90 x 2 2 6H 87.835 88.210 88.701 88.937 90.000 90.525
M95 x 2 2 6H 92.835 93.210 93.701 93.951 95.000 95.539
M100 x 6 6 6H 93.505 94.305 96.103 96.503 100.000 101.266
M100 x 2 2 6H 97.835 98.210 98.701 98.951 100.000 100.539
M105 x 2 2 6H 102.835 103.210 103.701 103.951 105.000 105.539
M110 x 2 2 6H 107.835 108.210 108.701 108.951 110.000 110.539
M120 x 2 2 6H 117.835 118.210 118.701 118.951 120.000 120.539
M130 x 2 2 6H 127.835 128.210 128.701 128.951 130.000 130.539
M140 x 2 2 6H 137.835 138.210 138.701 138.951 140.000 140.539
M150 x 2 2 6H 147.835 148.210 148.701 148.951 150.000 150.539
M160 x 3 3 6H 156.752 157.252 158.051 158.351 160.000 160.733
M170 x 3 3 6H 166.752 167.252 168.051 168.351 170.000 170.733
M180 x 3 3 6H 176.752 177.252 178.051 178.351 180.000 180.733
M190 x 3 3 6H 186.752 187.252 188.051 188.386 190.000 190.768
M200 x 3 3 6H 196.752 197.252 198.051 198.386 200.000 200.768

Note 1: Dimension is used in the design of tools, etc. In dimensioning internal threads it is not normally specified.

FAQ

What is the minor diameter (D1) for M3, M6 or M10 internal threads?

Select the thread designation in the calculator above (example: M3 x 0.5, M6 x 1, M10 x 1.5). The result shows D1 min and D1 max in mm.

What does 6H mean?

6H is a common ISO metric internal thread tolerance class. This chart lists limiting diameters for 6H internal threads per ASME B1.13M (M profile).

Is this the same as an ISO metric thread table?

This page follows ASME B1.13M. For a full ISO-focused calculator (external + internal), use the ISO metric thread calculator.

Supplements

References

  • 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 ed., Industrial Press Inc.