M5 Bolt Torque
An M5 8.8 bolt with a coarse M5×0.8 thread needs about 6.39 N·m (4.71 ft·lb) when dry and 4.80 N·m (3.54 ft·lb) when oiled, tightened to 70% of yield (clamp force 6.35 kN).
| Grade | Clamp forcepreload | Dryμ 0.15 | Oiledμ 0.11 | PTFE / moly pasteμ 0.06 |
|---|---|---|---|---|
| 4.6 | 2.38 kN536 lbf | 2.40 N·m1.77 ft·lb | 1.80 N·m1.33 ft·lb | 1.21 N·m0.89 ft·lb |
| 4.8 | 3.18 kN714 lbf | 3.19 N·m2.36 ft·lb | 2.40 N·m1.77 ft·lb | 1.61 N·m1.19 ft·lb |
| 5.6 | 2.98 kN670 lbf | 2.99 N·m2.21 ft·lb | 2.25 N·m1.66 ft·lb | 1.51 N·m1.11 ft·lb |
| 5.8 | 3.97 kN893 lbf | 3.99 N·m2.94 ft·lb | 3.00 N·m2.21 ft·lb | 2.01 N·m1.48 ft·lb |
| 6.8 | 4.77 kN1071 lbf | 4.79 N·m3.53 ft·lb | 3.60 N·m2.66 ft·lb | 2.42 N·m1.78 ft·lb |
| 8.8 | 6.35 kN1428 lbf | 6.39 N·m4.71 ft·lb | 4.80 N·m3.54 ft·lb | 3.22 N·m2.38 ft·lb |
| 9.8 | 7.15 kN1607 lbf | 7.19 N·m5.30 ft·lb | 5.40 N·m3.99 ft·lb | 3.62 N·m2.67 ft·lb |
| 10.9 | 8.93 kN2009 lbf | 8.98 N·m6.62 ft·lb | 6.76 N·m4.98 ft·lb | 4.53 N·m3.34 ft·lb |
| 12.9 | 10.7 kN2410 lbf | 10.8 N·m7.95 ft·lb | 8.11 N·m5.98 ft·lb | 5.43 N·m4.01 ft·lb |
| A2-70 | 4.47 kN1004 lbf | 4.49 N·m3.31 ft·lb | 3.38 N·m2.49 ft·lb | 2.26 N·m1.67 ft·lb |
| A4-70 | 4.47 kN1004 lbf | 4.49 N·m3.31 ft·lb | 3.38 N·m2.49 ft·lb | 2.26 N·m1.67 ft·lb |
| A4-80 | 5.96 kN1339 lbf | 5.99 N·m4.42 ft·lb | 4.50 N·m3.32 ft·lb | 3.02 N·m2.23 ft·lb |
| Grade | Clamp forcepreload | Dryμ 0.15 | Oiledμ 0.11 | PTFE / moly pasteμ 0.06 |
|---|---|---|---|---|
| 4.6 | 2.71 kN609 lbf | 2.64 N·m1.95 ft·lb | 1.95 N·m1.44 ft·lb | 1.26 N·m0.93 ft·lb |
| 4.8 | 3.61 kN812 lbf | 3.52 N·m2.59 ft·lb | 2.60 N·m1.92 ft·lb | 1.68 N·m1.24 ft·lb |
| 5.6 | 3.39 kN761 lbf | 3.30 N·m2.43 ft·lb | 2.44 N·m1.80 ft·lb | 1.58 N·m1.16 ft·lb |
| 5.8 | 4.51 kN1015 lbf | 4.40 N·m3.24 ft·lb | 3.25 N·m2.40 ft·lb | 2.10 N·m1.55 ft·lb |
| 6.8 | 5.42 kN1218 lbf | 5.28 N·m3.89 ft·lb | 3.90 N·m2.88 ft·lb | 2.52 N·m1.86 ft·lb |
| 8.8 | 7.22 kN1624 lbf | 7.03 N·m5.19 ft·lb | 5.20 N·m3.84 ft·lb | 3.37 N·m2.48 ft·lb |
| 9.8 | 8.13 kN1827 lbf | 7.91 N·m5.84 ft·lb | 5.85 N·m4.31 ft·lb | 3.79 N·m2.79 ft·lb |
| 10.9 | 10.2 kN2284 lbf | 9.89 N·m7.30 ft·lb | 7.31 N·m5.39 ft·lb | 4.73 N·m3.49 ft·lb |
| 12.9 | 12.2 kN2740 lbf | 11.9 N·m8.76 ft·lb | 8.78 N·m6.47 ft·lb | 5.68 N·m4.19 ft·lb |
| A2-70 | 5.08 kN1142 lbf | 4.95 N·m3.65 ft·lb | 3.66 N·m2.70 ft·lb | 2.37 N·m1.75 ft·lb |
| A4-70 | 5.08 kN1142 lbf | 4.95 N·m3.65 ft·lb | 3.66 N·m2.70 ft·lb | 2.37 N·m1.75 ft·lb |
| A4-80 | 6.77 kN1522 lbf | 6.59 N·m4.86 ft·lb | 4.88 N·m3.60 ft·lb | 3.16 N·m2.33 ft·lb |
Torque for M5 hex head bolts and nuts, standard ISO/ASME heads on steel with a 5.5 mm clearance hole. Friction μ applies to both the threads and the bearing face. Always follow the manufacturer's value where one exists.
M5 thread and dimensions
- Coarse thread
- M5×0.8 — pitch 0.8 mm
- Fine thread
- M5×0.5 — pitch 0.5 mm
- Tensile stress area Aₛ
- 14.2 mm² (coarse), 16.1 mm² (fine)
- Pitch diameter d₂
- 4.480 mm
- Tap drill
- 4.2 mm (coarse), 4.5 mm (fine)
- Wrench size (hex head)
- 8 mm
- Clearance hole
- 5.5 mm
How the M5 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 × 14.2 mm² = 6.35 kN
T = F × (0.16·P + 0.58·μ·d₂ + μ·Dₖₘ/2)
T = 6.35 kN × (0.16·0.8 + 0.58·0.15·4.48 + 0.15·6.75/2) mm = 6.39 N·m
Here d₂ is the pitch diameter and Dₖₘ the effective bearing diameter of the head (6.75 mm). Change the grade, lubrication or preload in the calculator below.
Frequently asked questions
What is the torque for an M5 8.8 bolt?
About 6.39 N·m (4.71 ft·lb) with dry threads, 4.80 N·m (3.54 ft·lb) with oiled threads and 3.22 N·m (2.38 ft·lb) with PTFE or moly paste, for a coarse M5×0.8 thread tightened to 70% of yield. The resulting clamp force is 6.35 kN.
What is the torque for an M5 10.9 bolt?
About 8.98 N·m (6.62 ft·lb) with dry threads, 6.76 N·m (4.98 ft·lb) with oiled threads and 4.53 N·m (3.34 ft·lb) with PTFE or moly paste, for a coarse M5×0.8 thread tightened to 70% of yield. The resulting clamp force is 8.93 kN.
What size wrench fits an M5 bolt?
A standard M5 hex head bolt or nut takes a 8 mm wrench or socket.
What drill size do I need to tap M5?
Use a 4.2 mm drill for M5×0.8 and 4.5 mm for M5×0.5.