Torque & Tension
Tightening Torque& Tension
ISO 898-1 / VDI 2230 recommended preload clamping tension and tightening torque for metric and imperial industrial fasteners, with an interactive friction-adjusted calculator.
Reference: ISO 898-1 · VDI 2230
ISO 898-1 / VDI 2230
Tightening Torque & Clamping Force Calculator
Preload at ~75–90% of proof load · friction-adjusted per VDI 2230
Standard conditions — good
206.0 Nm
Recommended Torque
68.3 kN
Preload Clamp Force
91.1 kN
Proof Load
100.5 kN
Yield Force
151.9 ft-lbs
Equivalent
1823.3 in-lbs
Equivalent
157 mm²
Stress Area Aₛ
2 mm
Pitch
Caution: Actual tightening result depends on joint stiffness, plating, surface finish and lubrication. Always verify with a calibrated torque wrench and confirm for safety-critical joints with an engineer.
Mechanical Property & Torque Reference
Preload, proof load and dry-torque (µ = 0.14) by diameter and property class
| Thread | Class | Yield (kN) | Proof (kN) | Preload (kN) | Torque Dry (Nm) | Torque Dry (ft-lbs) | Torque Oiled (Nm) |
|---|---|---|---|---|---|---|---|
| M4 | 4.6 | 2.1 | 2 | 1.5 | 1 | 0.74 | 0.85 |
| 8.8 | 5.6 | 5.1 | 3.8 | 3 | 2.21 | 2.5 | |
| 10.9 | 7.9 | 7.3 | 5.5 | 4.4 | 3.25 | 3.7 | |
| 12.9 | 9.5 | 8.5 | 6.4 | 5.1 | 3.76 | 4.3 | |
| A2-70 | 3.9 | 3.7 | 2.8 | 2.2 | 1.62 | 1.8 | |
| M5 | 4.6 | 3.4 | 3.2 | 2.4 | 2 | 1.48 | 1.7 |
| 8.8 | 9.1 | 8.2 | 6.2 | 5.9 | 4.35 | 5 | |
| 10.9 | 12.8 | 11.8 | 8.8 | 8.6 | 6.34 | 7.3 | |
| 12.9 | 15.3 | 13.8 | 10.3 | 10 | 7.38 | 8.5 | |
| A2-70 | 6.4 | 6 | 4.5 | 4.4 | 3.25 | 3.7 | |
| M6 | 4.6 | 4.8 | 4.5 | 3.4 | 3.9 | 2.88 | 3.3 |
| 8.8 | 12.9 | 11.7 | 8.8 | 10.1 | 7.45 | 8.6 | |
| 10.9 | 18.1 | 16.7 | 12.5 | 14.9 | 10.99 | 12.6 | |
| 12.9 | 21.7 | 19.5 | 14.6 | 17.4 | 12.83 | 14.7 | |
| A2-70 | 9 | 8.4 | 6.3 | 7.5 | 5.53 | 6.3 | |
| M8 | 4.6 | 8.8 | 8.2 | 6.2 | 9.5 | 7.01 | 8 |
| 8.8 | 23.4 | 21.2 | 15.9 | 24.6 | 18.14 | 20.9 | |
| 10.9 | 32.9 | 30.4 | 22.8 | 36.1 | 26.63 | 30.6 | |
| 12.9 | 39.5 | 35.5 | 26.6 | 42.2 | 31.13 | 35.8 | |
| A2-70 | 16.5 | 15.4 | 11.5 | 18.2 | 13.42 | 15.4 | |
| M10 | 4.6 | 13.9 | 13 | 9.8 | 18.8 | 13.87 | 15.9 |
| 8.8 | 37.1 | 33.6 | 25.2 | 48 | 35.4 | 41 | |
| 10.9 | 52.2 | 48.1 | 36.1 | 71 | 52.37 | 60 | |
| 12.9 | 62.6 | 56.3 | 42.2 | 83 | 61.22 | 70 | |
| A2-70 | 26.1 | 24.4 | 18.3 | 36 | 26.55 | 30 | |
| M12 | 4.6 | 20.2 | 19 | 14.2 | 33 | 24.34 | 28 |
| 8.8 | 54 | 48.9 | 36.7 | 84 | 61.95 | 71 | |
| 10.9 | 75.9 | 70 | 52.5 | 123 | 90.72 | 104 | |
| 12.9 | 91 | 81.8 | 61.3 | 144 | 106.21 | 122 | |
| A2-70 | 37.9 | 35.4 | 26.6 | 62 | 45.73 | 53 | |
| M14 | 4.6 | 27.6 | 25.9 | 19.4 | 53 | 39.09 | 45 |
| 8.8 | 73.6 | 66.7 | 50 | 133 | 98.1 | 113 | |
| 10.9 | 103.5 | 95.5 | 71.6 | 195 | 143.82 | 165 | |
| 12.9 | 124.2 | 111.6 | 83.7 | 228 | 168.16 | 194 | |
| A2-70 | 51.8 | 48.3 | 36.2 | 99 | 73.02 | 84 | |
| M16 | 4.6 | 37.7 | 35.3 | 26.5 | 82 | 60.48 | 70 |
| 8.8 | 100.5 | 91.1 | 68.3 | 206 | 151.94 | 175 | |
| 10.9 | 141.3 | 130.3 | 97.7 | 302 | 222.74 | 256 | |
| 12.9 | 169.6 | 152.3 | 114.2 | 353 | 260.36 | 300 | |
| A2-70 | 70.7 | 65.9 | 49.4 | 153 | 112.85 | 130 | |
| B7 | 113 | 102 | 76.5 | 235 | 173.33 | 200 | |
| M20 | 4.6 | 58.8 | 55.1 | 41.3 | 160 | 118.01 | 136 |
| 8.8 | 156.8 | 142.1 | 106.6 | 402 | 296.5 | 341 | |
| 10.9 | 220.5 | 203.4 | 152.5 | 590 | 435.16 | 501 | |
| 12.9 | 264.6 | 237.7 | 178.2 | 690 | 508.92 | 586 | |
| A2-70 | 110.3 | 102.9 | 77.2 | 298 | 219.79 | 253 | |
| B7 | 176.4 | 159.3 | 119.4 | 460 | 339.28 | 391 | |
| M24 | 4.6 | 84.7 | 79.4 | 59.6 | 276 | 203.57 | 235 |
| 8.8 | 225.9 | 204.7 | 153.6 | 696 | 513.34 | 592 | |
| 10.9 | 317.7 | 293 | 219.7 | 1020 | 752.31 | 867 | |
| 12.9 | 381.2 | 342.4 | 256.8 | 1190 | 877.7 | 1011 | |
| A2-70 | 158.9 | 148.3 | 111.2 | 515 | 379.84 | 438 | |
| B7 | 254.2 | 229.5 | 172.1 | 795 | 586.35 | 676 | |
| M30 | 4.6 | 134.6 | 126.2 | 94.7 | 550 | 405.66 | 468 |
| 8.8 | 359 | 325.4 | 244 | 1380 | 1017.84 | 1173 | |
| 10.9 | 504.9 | 465.6 | 349.2 | 2030 | 1497.25 | 1725 | |
| 12.9 | 605.9 | 544.2 | 408.1 | 2370 | 1748.02 | 2014 | |
| B7 | 403.9 | 364.7 | 273.5 | 1575 | 1161.66 | 1339 | |
| M36 | 4.6 | 196.1 | 183.8 | 137.9 | 960 | 708.06 | 816 |
| 8.8 | 522.9 | 473.9 | 355.4 | 2410 | 1777.52 | 2048 | |
| 10.9 | 735.3 | 678.1 | 508.6 | 3540 | 2610.97 | 3009 | |
| 12.9 | 882.4 | 792.5 | 594.4 | 4140 | 3053.52 | 3519 | |
| B7 | 588.2 | 531.1 | 398.3 | 2750 | 2028.3 | 2337 |