# Bolt torque chart

Dry tightening torque for coarse-thread steel bolts at 75 % of proof load. Data: https://machinistcharts.com/data/bolt-torque.csv

## Metric bolts, dry torque (N·m)

| Size | Class 8.8 | Class 10.9 | Class 12.9 | Wrench |
|---|---|---|---|---|
| M4 x 0.7 | 3.1 | 4.4 | 5.1 | 7 mm |
| M5 x 0.8 | 6.2 | 8.8 | 10 | 8 mm |
| M6 x 1 | 11 | 15 | 18 | 10 mm |
| M8 x 1.25 | 25 | 36 | 43 | 13 mm |
| M10 x 1.5 | 50 | 72 | 84 | 16 mm |
| M12 x 1.75 | 88 | 126 | 147 | 18 mm |
| M14 x 2 | 141 | 201 | 235 | 21 mm |
| M16 x 2 | 218 | 312 | 365 | 24 mm |
| M18 x 2.5 | 312 | 431 | 504 | 27 mm |
| M20 x 2.5 | 441 | 610 | 712 | 30 mm |
| M22 x 2.5 | 601 | 831 | 971 | 34 mm |
| M24 x 3 | 761 | 1,053 | 1,231 | 36 mm |
| M27 x 3 | 1,116 | 1,544 | 1,805 | 41 mm |
| M30 x 3.5 | 1,514 | 2,094 | 2,447 | 46 mm |
| M33 x 3.5 | 2,060 | 2,849 | 3,330 | 50 mm |
| M36 x 4 | 2,646 | 3,661 | 4,278 | 55 mm |

## Inch bolts, UNC, dry torque (ft-lb)

| Size | Grade 2 | Grade 5 | Grade 8 | Wrench |
|---|---|---|---|---|
| 1/4-20 | 5.5 | 8.5 | 12 | 7/16 in |
| 5/16-18 | 11 | 17 | 25 | 1/2 in |
| 3/8-16 | 20 | 31 | 44 | 9/16 in |
| 7/16-14 | 32 | 49 | 70 | 5/8 in |
| 1/2-13 | 49 | 75 | 106 | 3/4 in |
| 9/16-12 | 70 | 109 | 154 | 13/16 in |
| 5/8-11 | 97 | 150 | 212 | 15/16 in |
| 3/4-10 | 172 | 267 | 376 | 1-1/8 in |
| 7/8-9 | 167 | 429 | 606 | 1-5/16 in |
| 1-8 | 250 | 644 | 909 | 1-1/2 in |

## Method

T = K x F x d. F (target clamp load) = 75 % of proof load. Proof load = proof stress x tensile stress area. Proof stress: ISO 898-1 (8.8: 580 MPa up to M16, 600 MPa above; 10.9: 830 MPa; 12.9: 970 MPa), SAE J429 (grade 2: 55 ksi to 3/4 in, 33 ksi above; grade 5: 85 ksi to 1 in; grade 8: 120 ksi). Stress area: metric As = pi/4 x (d - 0.9382 p)^2; inch As = 0.7854 x (D - 0.9743/n)^2. K = 0.20 dry, 0.15 lubricated.

Source page: https://machinistcharts.com/bolt-torque/
Updated: 2026-10-05
Publisher: MachinistCharts (https://machinistcharts.com)