M12 Bolt Torque
An M12 8.8 bolt with a coarse M12×1.75 thread needs about 89.2 N·m (65.8 ft·lb) when dry and 66.8 N·m (49.3 ft·lb) when oiled, tightened to 70% of yield (clamp force 37.8 kN).
| Grade | Clamp forcepreload | Dryμ 0.15 | Oiledμ 0.11 | PTFE / moly pasteμ 0.06 |
|---|---|---|---|---|
| 4.6 | 14.2 kN3183 lbf | 33.4 N·m24.7 ft·lb | 25.1 N·m18.5 ft·lb | 16.7 N·m12.3 ft·lb |
| 4.8 | 18.9 kN4243 lbf | 44.6 N·m32.9 ft·lb | 33.4 N·m24.6 ft·lb | 22.3 N·m16.4 ft·lb |
| 5.6 | 17.7 kN3978 lbf | 41.8 N·m30.8 ft·lb | 31.3 N·m23.1 ft·lb | 20.9 N·m15.4 ft·lb |
| 5.8 | 23.6 kN5304 lbf | 55.7 N·m41.1 ft·lb | 41.8 N·m30.8 ft·lb | 27.8 N·m20.5 ft·lb |
| 6.8 | 28.3 kN6365 lbf | 66.9 N·m49.3 ft·lb | 50.1 N·m37.0 ft·lb | 33.4 N·m24.6 ft·lb |
| 8.8 | 37.8 kN8487 lbf | 89.2 N·m65.8 ft·lb | 66.8 N·m49.3 ft·lb | 44.5 N·m32.8 ft·lb |
| 9.8 | 42.5 kN9548 lbf | 100.3 N·m74.0 ft·lb | 75.2 N·m55.5 ft·lb | 50.1 N·m36.9 ft·lb |
| 10.9 | 53.1 kN11935 lbf | 125.4 N·m92.5 ft·lb | 94.0 N·m69.3 ft·lb | 62.6 N·m46.2 ft·lb |
| 12.9 | 63.7 kN14322 lbf | 150.5 N·m111.0 ft·lb | 112.8 N·m83.2 ft·lb | 75.1 N·m55.4 ft·lb |
| A2-70 | 26.5 kN5967 lbf | 62.7 N·m46.2 ft·lb | 47.0 N·m34.7 ft·lb | 31.3 N·m23.1 ft·lb |
| A4-70 | 26.5 kN5967 lbf | 62.7 N·m46.2 ft·lb | 47.0 N·m34.7 ft·lb | 31.3 N·m23.1 ft·lb |
| A4-80 | 35.4 kN7956 lbf | 83.6 N·m61.6 ft·lb | 62.7 N·m46.2 ft·lb | 41.7 N·m30.8 ft·lb |
| Grade | Clamp forcepreload | Dryμ 0.15 | Oiledμ 0.11 | PTFE / moly pasteμ 0.06 |
|---|---|---|---|---|
| 4.6 | 14.8 kN3328 lbf | 34.6 N·m25.5 ft·lb | 25.8 N·m19.0 ft·lb | 17.0 N·m12.5 ft·lb |
| 4.8 | 19.7 kN4438 lbf | 46.1 N·m34.0 ft·lb | 34.4 N·m25.3 ft·lb | 22.6 N·m16.7 ft·lb |
| 5.6 | 18.5 kN4160 lbf | 43.2 N·m31.9 ft·lb | 32.2 N·m23.8 ft·lb | 21.2 N·m15.6 ft·lb |
| 5.8 | 24.7 kN5547 lbf | 57.6 N·m42.5 ft·lb | 42.9 N·m31.7 ft·lb | 28.3 N·m20.8 ft·lb |
| 6.8 | 29.6 kN6657 lbf | 69.2 N·m51.0 ft·lb | 51.5 N·m38.0 ft·lb | 33.9 N·m25.0 ft·lb |
| 8.8 | 39.5 kN8876 lbf | 92.2 N·m68.0 ft·lb | 68.7 N·m50.7 ft·lb | 45.2 N·m33.3 ft·lb |
| 9.8 | 44.4 kN9985 lbf | 103.7 N·m76.5 ft·lb | 77.3 N·m57.0 ft·lb | 50.9 N·m37.5 ft·lb |
| 10.9 | 55.5 kN12481 lbf | 129.7 N·m95.6 ft·lb | 96.6 N·m71.3 ft·lb | 63.6 N·m46.9 ft·lb |
| 12.9 | 66.6 kN14977 lbf | 155.6 N·m114.8 ft·lb | 115.9 N·m85.5 ft·lb | 76.3 N·m56.3 ft·lb |
| A2-70 | 27.8 kN6241 lbf | 64.8 N·m47.8 ft·lb | 48.3 N·m35.6 ft·lb | 31.8 N·m23.4 ft·lb |
| A4-70 | 27.8 kN6241 lbf | 64.8 N·m47.8 ft·lb | 48.3 N·m35.6 ft·lb | 31.8 N·m23.4 ft·lb |
| A4-80 | 37.0 kN8321 lbf | 86.4 N·m63.8 ft·lb | 64.4 N·m47.5 ft·lb | 42.4 N·m31.3 ft·lb |
Torque for M12 hex head bolts and nuts, standard ISO/ASME heads on steel with a 13.5 mm clearance hole. Friction μ applies to both the threads and the bearing face. Always follow the manufacturer's value where one exists.
M12 thread and dimensions
- Coarse thread
- M12×1.75 — pitch 1.75 mm
- Fine thread
- M12×1.5 — pitch 1.5 mm
- Tensile stress area Aₛ
- 84.3 mm² (coarse), 88.1 mm² (fine)
- Pitch diameter d₂
- 10.863 mm
- Tap drill
- 10.2 mm (coarse), 10.5 mm (fine)
- Wrench size (hex head)
- 18 mm (DIN: 19 mm)
- Clearance hole
- 13.5 mm
How the M12 torque is calculated
Preload is 70% of the bolt's yield strength times its tensile stress area. Torque then follows the ISO 16047 / VDI 2230 formula, which splits it into thread pitch, thread friction and friction under the head:
F = 70% × 640 MPa × 84.3 mm² = 37.8 kN
T = F × (0.16·P + 0.58·μ·d₂ + μ·Dₖₘ/2)
T = 37.8 kN × (0.16·1.75 + 0.58·0.15·10.86 + 0.15·15.75/2) mm = 89.2 N·m
Here d₂ is the pitch diameter and Dₖₘ the effective bearing diameter of the head (15.75 mm). Change the grade, lubrication or preload in the calculator below.
Frequently asked questions
What is the torque for an M12 8.8 bolt?
About 89.2 N·m (65.8 ft·lb) with dry threads, 66.8 N·m (49.3 ft·lb) with oiled threads and 44.5 N·m (32.8 ft·lb) with PTFE or moly paste, for a coarse M12×1.75 thread tightened to 70% of yield. The resulting clamp force is 37.8 kN.
What is the torque for an M12 10.9 bolt?
About 125.4 N·m (92.5 ft·lb) with dry threads, 94.0 N·m (69.3 ft·lb) with oiled threads and 62.6 N·m (46.2 ft·lb) with PTFE or moly paste, for a coarse M12×1.75 thread tightened to 70% of yield. The resulting clamp force is 53.1 kN.
What size wrench fits an M12 bolt?
A standard M12 hex head bolt or nut takes a 18 mm (DIN: 19 mm) wrench or socket.
What drill size do I need to tap M12?
Use a 10.2 mm drill for M12×1.75 and 10.5 mm for M12×1.5.