Metric bolt torque chart
At 75% of proof load, an M10 x 1.5 bolt takes 50 N·m in class 8.8, 72 N·m in 10.9 and 84 N·m in 12.9, dry; oiled threads take a quarter less. The chart covers M5 to M36 in coarse and fine thread.
Sources checked
| Thread | Class 4.6 | Class 8.8 | Class 10.9 | Class 12.9 | ||||
|---|---|---|---|---|---|---|---|---|
| Dry | Oiled | Dry | Oiled | Dry | Oiled | Dry | Oiled | |
| M5 x 0.8coarse | 1.82.4 | 1.31.8 | 4.66.2 | 3.44.6 | 6.58.8 | 4.96.6 | 7.610.3 | 5.77.7 |
| M6 x 1coarse | 3.04.1 | 2.33.1 | 7.710.5 | 5.87.9 | 11.115.0 | 8.311.3 | 12.917.5 | 9.713.2 |
| M8 x 1.25coarse | 7.39.9 | 5.57.4 | 18.825.5 | 14.119.1 | 26.936.5 | 20.227.3 | 31.442.6 | 23.632.0 |
| M8 x 1fine | 7.810.6 | 5.97.9 | 20.127.3 | 15.120.5 | 28.839.0 | 21.629.3 | 33.745.6 | 25.234.2 |
| M10 x 1.5coarse | 14.419.6 | 10.814.7 | 37.250.5 | 27.937.8 | 53.372.2 | 39.954.2 | 62.284.4 | 46.763.3 |
| M10 x 1.25fine | 15.220.7 | 11.415.5 | 39.353.2 | 29.539.9 | 56.276.2 | 42.157.1 | 65.789.0 | 49.366.8 |
| M10 x 1fine | 16.121.8 | 12.016.3 | 41.456.1 | 31.042.1 | 59.280.3 | 44.460.2 | 69.293.8 | 51.970.4 |
| M12 x 1.75coarse | 25.234.1 | 18.925.6 | 64.988.0 | 48.766.0 | 92.9126 | 69.794.5 | 109147 | 81.4110 |
| M12 x 1.5fine | 26.335.7 | 19.726.8 | 67.892.0 | 50.969.0 | 97.1132 | 72.898.7 | 113154 | 85.1115 |
| M12 x 1.25fine | 27.537.3 | 20.628.0 | 70.996.2 | 53.272.1 | 101138 | 76.1103 | 119161 | 89.0121 |
| M14 x 2coarse | 40.154.3 | 30.140.8 | 103140 | 77.5105 | 148200 | 111150 | 173234 | 130176 |
| M14 x 1.5fine | 43.659.1 | 32.744.3 | 112152 | 84.2114 | 161218 | 121163 | 188255 | 141191 |
| M16 x 2coarse | 62.584.8 | 46.963.6 | 161219 | 121164 | 231313 | 173235 | 270365 | 202274 |
| M16 x 1.5fine | 66.590.2 | 49.967.6 | 171232 | 129174 | 245333 | 184249 | 287389 | 215292 |
| M18 x 2.5coarse | 86.0117 | 64.587.5 | 229311 | 172233 | 317430 | 238323 | 371503 | 278377 |
| M18 x 1.5fine | 96.8131 | 72.698.4 | 258350 | 194262 | 357484 | 268363 | 417566 | 313424 |
| M20 x 2.5coarse | 122165 | 91.5124 | 325441 | 244331 | 450610 | 337458 | 526713 | 394535 |
| M20 x 1.5fine | 135184 | 102138 | 361490 | 271367 | 500677 | 375508 | 584792 | 438594 |
| M22 x 2.5coarse | 166225 | 124169 | 442600 | 332450 | 612830 | 459622 | 715970 | 537727 |
| M22 x 1.5fine | 182247 | 137185 | 486659 | 365495 | 673912 | 505684 | 7861,066 | 590799 |
| M24 x 3coarse | 211286 | 158214 | 562762 | 422572 | 7781,055 | 583791 | 9091,233 | 682925 |
| M24 x 2fine | 229311 | 172233 | 612829 | 459622 | 8461,147 | 635861 | 9891,341 | 7421,006 |
| M27 x 3coarse | 308418 | 231314 | 8231,115 | 617837 | 1,1381,543 | 8541,157 | 1,3301,803 | 9971,352 |
| M27 x 2fine | 333452 | 250339 | 8891,205 | 667904 | 1,2301,667 | 9221,250 | 1,4371,949 | 1,0781,461 |
| M30 x 3.5coarse | 419568 | 314426 | 1,1171,515 | 8381,136 | 1,5452,095 | 1,1591,572 | 1,8062,449 | 1,3551,837 |
| M30 x 2fine | 464629 | 348472 | 1,2371,677 | 9281,258 | 1,7112,319 | 1,2831,740 | 1,9992,711 | 1,4992,033 |
| M36 x 4coarse | 732993 | 549744 | 1,9522,647 | 1,4641,985 | 2,7013,662 | 2,0262,746 | 3,1564,279 | 2,3673,210 |
| M36 x 3fine | 7751,051 | 581788 | 2,0672,803 | 1,5502,102 | 2,8593,877 | 2,1452,908 | 3,3424,531 | 2,5063,398 |
Class 8.8 proof stress is 580 MPa up to M16 and 600 MPa above. Open a size for zinc-plated and waxed values and clamp loads:
How to read the chart
Find the bolt’s diameter and pitch on the left, then its property class across the top: the class is stamped on the head (bolt grade markings). Coarse pitch is the default thread; fine pitches are listed under it. Take the dry value for clean, unlubricated threads and the oiled value when they’re oiled.
Every value is the torque that clamps the bolt to 75% of its proof load, from T = K × d × F with K 0.20 dry and 0.15 oiled, the same assumptions as Fastenal’s metric chart, and the numbers match it. To change them, use the bolt torque calculator.
Where these numbers stop
A maker’s spec beats the chart
Car, motorcycle and machine makers publish torques for their own joints, often lower than a bare bolt could take. Use them first. The chart is for general-purpose steel bolts to ISO 898-1 where no spec exists.
Stainless (A2, A4) and torque-to-yield bolts aren’t covered.
Questions
What torque for an M8 bolt?
An M8 x 1.25 bolt at 75% of proof load, dry, takes 25.5 N·m in class 8.8, 36.5 N·m in 10.9 and 42.6 N·m in 12.9 (19 ft-lb, 27 ft-lb and 31 ft-lb). Oiled threads take a quarter less.
What does 8.8 mean on a bolt?
It’s the ISO 898-1 property class. The first number is a tenth of the tensile strength in MPa (8 → 800 MPa), and the second is the yield strength as a fraction of it (.8 → 80%). Higher classes are stronger: 10.9 and 12.9 are alloy steel.
Why does class 8.8 change at M16?
ISO 898-1 sets a proof stress of 580 MPa for class 8.8 up to M16 and 600 MPa above it, so bolts from M18 up are allowed a little more.
Can I tighten a metric bolt in ft-lb?
Yes: the chart switches units, and the torque converter does any value. 1 N·m is 0.738 ft-lb.
Sources
- Fastenal: Mechanical properties per ISO 898-1 (externally threaded fasteners): proof stress by property class (checked October 14, 2026)
- Engineering Toolbox: Metric bolts: minimum ultimate tensile and proof loads, with ISO 898-1 stress areas (checked October 14, 2026)
- Engineering Toolbox: ISO 724 metric threads: coarse and fine pitches with tensile stress areas (checked October 14, 2026)
- Fastenal: Torque–tension relationship for metric fasteners, property classes 4.6, 8.8, 10.9 and 12.9 (checked October 14, 2026)
- Fastenal: Bolted joint design: nut factor (K) by finish and how much preload varies at a given torque (checked October 14, 2026)
- Bolt Depot: Bolt grade markings and strength chart (checked October 14, 2026)
Spotted a number that doesn’t match your manual or a source? Tell us; corrections are logged on the sources page.