ISO Metric Thread Dimensions
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The ISO Standardisation Authority defines strict specifications metric threads. This is to ensure compatibility with mating components. The table below shows various dimensions and the required tap drill diameter of coarse and fine threads M1 through to M68.
Tolerances should be considered when designing products. Values related to drilling and tapping can differ significantly depending on factors such as operating temperature and material.
Optimas are a full-service supply chain and manufacturing solutions provider. Before you design your next product or make updates to an existing product, consider partnering with Optimas to take advantage of our many capabilities.
All dimensions in millimeters (mm). For guidance only.
Thread |
Major Diameter (d=D) |
Pitch (p) |
Root Radius (r) |
Pitch Diameter (d2=D2) |
Minor Diameter Male Thread (d3) |
Minor Diameter Female Thread (D1) |
Thread Height Male Thread (h3) |
Thread Height Female Thread (H1) |
Tap Drill Diameter |
---|---|---|---|---|---|---|---|---|---|
M1 | 1 | 0.25 | 0.036 | 0.838 | 0.693 | 0.729 | 0.153 | 0.135 | 0.75 |
M1.1 | 1.1 | 0.25 | 0.036 | 0.938 | 0.793 | 0.829 | 0.153 | 0.135 | 0.85 |
M1.2 | 1.2 | 0.25 | 0.036 | 1.038 | 0.893 | 0.929 | 0.153 | 0.135 | 0.95 |
M1.4 | 1.4 | 0.3 | 0.043 | 1.205 | 1.032 | 1.075 | 0.184 | 0.162 | 1.1 |
M1.6 | 1.6 | 0.35 | 0.051 | 1.373 | 1.171 | 1.221 | 0.215 | 0.189 | 1.25 |
M1.8 | 1.8 | 0.35 | 0.051 | 1.573 | 1.371 | 1.421 | 0.215 | 0.189 | 1.45 |
M2 | 2 | 0.4 | 0.058 | 1.74 | 1.509 | 1.567 | 0.245 | 0.217 | 1.6 |
M2.2 | 2.2 | 0.45 | 0.065 | 1.908 | 1.648 | 1.713 | 0.276 | 0.244 | 1.75 |
M2.5 | 2.5 | 0.45 | 0.065 | 2.208 | 1.948 | 2.013 | 0.276 | 0.244 | 2.05 |
M3 | 3 | 0.5 | 0.072 | 2.675 | 2.387 | 2.459 | 0.307 | 0.271 | 2.5 |
M3.5 | 3.5 | 0.6 | 0.087 | 3.11 | 2.764 | 2.85 | 0.368 | 0.325 | 2.9 |
M4 | 4 | 0.7 | 0.101 | 3.545 | 3.141 | 3.242 | 0.429 | 0.379 | 3.3 |
M4.5 | 4.5 | 0.75 | 0.108 | 4.013 | 3.58 | 3.688 | 0.46 | 0.406 | 3.8 |
M5 | 5 | 0.8 | 0.115 | 4.48 | 4.019 | 4.134 | 0.491 | 0.433 | 4.2 |
M6 | 6 | 1 | 0.144 | 5.35 | 4.773 | 4.917 | 0.613 | 0.541 | 5 |
M7 | 7 | 1 | 0.144 | 6.35 | 5.773 | 5.917 | 0.613 | 0.541 | 6 |
M8 | 8 | 1.25 | 0.18 | 7.188 | 6.466 | 6.647 | 0.767 | 0.677 | 6.8 |
M9 | 9 | 1.25 | 0.18 | 8.188 | 7.466 | 7.647 | 0.767 | 0.677 | 7.8 |
M10 | 10 | 1.5 | 0.217 | 9.026 | 8.16 | 8.376 | 0.92 | 0.812 | 8.5 |
M11 | 11 | 1.5 | 0.217 | 10.026 | 9.16 | 9.376 | 0.92 | 0.812 | 9.5 |
M12 | 12 | 1.75 | 0.253 | 10.863 | 9.853 | 10.106 | 1.074 | 0.947 | 10.2 |
M14 | 14 | 2 | 0.289 | 12.701 | 11.564 | 11.835 | 1.227 | 1.083 | 12 |
M16 | 16 | 2 | 0.289 | 14.701 | 13.546 | 13.835 | 1.227 | 1.083 | 14 |
M18 | 18 | 2.5 | 0.361 | 16.376 | 14.933 | 15.394 | 1.534 | 1.353 | 15.5 |
M20 | 20 | 2.5 | 0.361 | 18.376 | 16.933 | 17.294 | 1.534 | 1.353 | 17.5 |
M22 | 22 | 2.5 | 0.361 | 20.376 | 18.933 | 19.294 | 1.534 | 1.353 | 19.5 |
M24 | 24 | 3 | 0.433 | 22.051 | 20.319 | 20.752 | 1.84 | 1.624 | 21 |
M27 | 27 | 3 | 0.433 | 25.051 | 23.319 | 23.752 | 1.84 | 1.624 | 24 |
M30 | 30 | 3.5 | 0.505 | 27.727 | 25.706 | 26.211 | 2.147 | 1.894 | 26.5 |
M33 | 33 | 3.5 | 0.505 | 30.727 | 28.706 | 29.211 | 2.147 | 1.894 | 29.5 |
M36 | 36 | 4 | 0.577 | 33.402 | 31.093 | 31.67 | 2.454 | 2.165 | 32 |
M39 | 39 | 4 | 0.577 | 36.402 | 34.093 | 34.67 | 2.454 | 2.165 | 35 |
M42 | 42 | 4.5 | 0.65 | 39.077 | 36.479 | 37.129 | 2.76 | 2.436 | 37.5 |
M45 | 45 | 4.5 | 0.65 | 42.077 | 39.479 | 40.129 | 2.76 | 2.436 | 40.5 |
M48 | 48 | 5 | 0.722 | 44.752 | 41.866 | 42.857 | 3.067 | 2.706 | 43 |
M52 | 52 | 5 | 0.722 | 48.752 | 45.866 | 46.857 | 3.067 | 2.706 | 47 |
M56 | 56 | 5.5 | 0.794 | 52.428 | 49.252 | 50.046 | 3.374 | 2.977 | 50.5 |
M60 | 60 | 5.5 | 0.794 | 56.428 | 53.252 | 54.046 | 3.374 | 2.977 | 54.5 |
M64 | 64 | 6 | 0.866 | 60.103 | 56.639 | 57.505 | 3.681 | 3.248 | 58 |
M68 | 68 | 6 | 0.866 | 64.103 | 60.639 | 61.505 | 3.681 | 3.248 | 62 |
Thread Size |
Major Diameter d=D |
Pitch p |
Root Radius r |
Pitch Diameter d2=D2 |
Minor Diameter Male Thread d3 |
Minor Diameter Female Thread D1 |
Thread Height Male Thread h3 |
Thread Height Female Thread H1 |
Tap Drill Diameter |
---|---|---|---|---|---|---|---|---|---|
M1.0 x 0.2 | 1 | 0.2 | 0.029 | 0.87 | 0.755 | 0.783 | 0.123 | 0.108 | 0.8 |
M1.1 x 0.2 | 1.1 | 0.2 | 0.029 | 0.97 | 0.855 | 0.883 | 0.123 | 0.108 | 0.9 |
M1.2 x 0.2 | 1.2 | 0.2 | 0.029 | 1.07 | 0.955 | 0.983 | 0.123 | 0.108 | 1 |
M1.4 x 0.2 | 1.4 | 0.2 | 0.029 | 1.27 | 1.155 | 1.183 | 0.123 | 0.108 | 1.2 |
M1.6 x 0.2 | 1.6 | 0.2 | 0.029 | 1.47 | 1.355 | 1.383 | 0.123 | 0.108 | 1.4 |
M1.8 x 0.2 | 1.8 | 0.2 | 0.029 | 1.67 | 1.555 | 1.583 | 0.123 | 0.108 | 1.6 |
M2 x 0.25 | 2 | 0.25 | 0.036 | 1.838 | 1.693 | 1.729 | 0.153 | 0.135 | 1.75 |
M2.2 x 0.25 | 2.2 | 0.25 | 0.036 | 2.038 | 1.893 | 1.929 | 0.153 | 0.135 | 1.95 |
M2.5 x 0.35 | 2.5 | 0.35 | 0.051 | 2.273 | 2.071 | 2.121 | 0.215 | 0.189 | 2.1 |
M3 x 0.35 | 3 | 0.35 | 0.051 | 2.773 | 2.571 | 2.621 | 0.215 | 0.189 | 2.6 |
M3.5 x 0.35 | 3.5 | 0.35 | 0.051 | 3.273 | 3.071 | 3.121 | 0.215 | 0.189 | 3.1 |
M4 x 0.5 | 4 | 0.5 | 0.072 | 3.675 | 3.387 | 3.459 | 0.307 | 0.271 | 3.5 |
M4.5 x 0.5 | 4.5 | 0.5 | 0.072 | 4.175 | 3.887 | 3.959 | 0.307 | 0.271 | 4 |
M5 x 0.5 | 5 | 0.5 | 0.072 | 4.675 | 4.387 | 4.459 | 0.307 | 0.271 | 4.5 |
M5.5 x 0.5 | 5.5 | 0.5 | 0.072 | 5.175 | 4.887 | 4.959 | 0.307 | 0.271 | 5 |
M6 x 0.75 | 6 | 0.75 | 0.108 | 5.513 | 5.08 | 5.188 | 0.46 | 0.406 | 5.2 |
M7 x 0.75 | 7 | 0.75 | 0.108 | 6.513 | 6.08 | 6.188 | 0.46 | 0.406 | 6.2 |
M8 x 0.75 | 8 | 0.75 | 0.108 | 7.513 | 7.08 | 7.188 | 0.46 | 0.406 | 7.2 |
M8 x 1.0 | 8 | 1 | 0.144 | 7.35 | 6.773 | 6.917 | 0.613 | 0.541 | 7 |
M9 x 0.75 | 9 | 0.75 | 0.108 | 8.513 | 8.08 | 8.188 | 0.46 | 0.406 | 8.2 |
M9 x 1 | 9 | 1 | 0.144 | 8.35 | 7.773 | 7.917 | 0.613 | 0.541 | 8 |
M10 x 0.75 | 10 | 0.75 | 0.108 | 9.513 | 9.08 | 9.188 | 0.46 | 0.406 | 9.2 |
M10 x 1 | 10 | 1 | 0.144 | 9.35 | 8.773 | 8.917 | 0.613 | 0.541 | 9 |
M10 x 1.25 | 10 | 1.25 | 0.18 | 9.188 | 8.466 | 8.647 | 0.767 | 0.677 | 8.8 |
M11 x 0.75 | 11 | 0.75 | 0.108 | 10.513 | 10.08 | 10.188 | 0.46 | 0.406 | 10.2 |
M11 x 1 | 11 | 1 | 0.144 | 10.35 | 9.773 | 9.917 | 0.613 | 0.541 | 10 |
M12 x 1 | 12 | 1 | 0.144 | 11.35 | 10.773 | 10.917 | 0.613 | 0.541 | 11 |
M12 x 1.25 | 12 | 1.25 | 0.18 | 11.188 | 10.466 | 10.647 | 0.767 | 0.677 | 10.8 |
M12 x 1.5 | 12 | 1.5 | 0.217 | 11.026 | 10.16 | 10.376 | 0.92 | 0.812 | 10.5 |
M14 x 1 | 14 | 1 | 0.144 | 13.35 | 12.773 | 12.917 | 0.613 | 0.541 | 13 |
M14 x 1.25 | 14 | 1.25 | 0.18 | 13.188 | 12.466 | 12.647 | 0.767 | 0.677 | 12.8 |
M14 x 1.5 | 14 | 1.5 | 0.217 | 13.026 | 12.16 | 12.376 | 0.92 | 0.812 | 12.5 |
M15 x 1 | 15 | 1 | 0.144 | 14.35 | 13.773 | 13.917 | 0.613 | 0.541 | 14 |
M15 x 1.5 | 15 | 1.5 | 0.217 | 14.026 | 13.16 | 13.376 | 0.92 | 0.812 | 13.5 |
M16 x 1 | 16 | 1 | 0.144 | 15.35 | 14.773 | 14.917 | 0.613 | 0.541 | 15 |
M16 x 1.5 | 16 | 1.5 | 0.217 | 15.026 | 14.16 | 14.376 | 0.92 | 0.812 | 14.5 |
M17 x 1 | 17 | 1 | 0.144 | 16.35 | 15.733 | 15.917 | 0.613 | 0.541 | 16 |
M17 x 1.5 | 17 | 1.5 | 0.217 | 16.026 | 15.16 | 15.376 | 0.92 | 0.812 | 15.5 |
M18 x 1 | 18 | 1 | 0.144 | 17.35 | 16.773 | 16.917 | 0.613 | 0.541 | 17 |
M18 x 1.5 | 18 | 1.5 | 0.217 | 17.026 | 16.16 | 16.376 | 0.92 | 0.812 | 16.5 |
M18 x 2 | 18 | 2 | 0.289 | 16.701 | 15.546 | 15.835 | 1.227 | 1.083 | 16 |
M20 x 1.0 | 20 | 1 | 0.144 | 19.35 | 18.773 | 18.917 | 0.613 | 0.541 | 19 |
M20 x 1.5 | 20 | 1.5 | 0.217 | 19.026 | 18.16 | 18.376 | 0.92 | 0.812 | 18.5 |
M20 x 2.0 | 20 | 2 | 0.289 | 18.701 | 17.546 | 17.835 | 1.227 | 1.083 | 18 |
M22 x 1.0 | 22 | 1 | 0.144 | 21.35 | 20.773 | 20.917 | 0.613 | 0.541 | 21 |
M22 x 1.5 | 22 | 1.5 | 0.217 | 21.026 | 20.16 | 20.376 | 0.92 | 0.812 | 20.5 |
M22 x 2.0 | 22 | 2 | 0.289 | 20.701 | 19.546 | 19.835 | 1.227 | 1.083 | 20 |
M24 x 1.0 | 24 | 1 | 0.144 | 23.35 | 22.773 | 22.917 | 0.613 | 0.541 | 23 |
M24 x 1.5 | 24 | 1.5 | 0.217 | 23.026 | 22.16 | 22.376 | 0.92 | 0.812 | 22.5 |
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