Metric bolt torque chart (8.8, 10.9 and 12.9)
An M12 x 1.75 class 8.8 bolt takes 65 ft-lb (88 N·m) plain and dry or 49 ft-lb (66 N·m) oiled; class 10.9 takes 93 ft-lb (126 N·m) dry. Values cover coarse threads M3 to M30 at 75% of ISO 898-1 proof load.
Contents7 sections
Key takeaways
- Dry values use K 0.20 and oiled values K 0.15, both at 75% of proof load 1.
- Class 8.8 proof stress is 580 MPa up to M16 and 600 MPa above 2.
- Class 10.9 takes about 43% more torque than 8.8 up to M16, and about 38% more above.
- Published M12 8.8 values range from about 74 to 100 N·m, because charts use different bases.
Quick facts
| Sizes | M3 to M30, coarse pitch |
|---|---|
| Clamp basis | 75% of ISO 898-1 proof load |
| Dry / oiled K | 0.20 / 0.15 |
Metric bolt torque chart (ft-lb / in-lb)
Coarse thread, clamp load 75% of proof load. Dry is plain steel K 0.201; oiled is a lubricated thread K 0.151. Fine threads, zinc-plated and anti-seize values are on each size page.
| Size | Class 4.6 | Class 8.8 | Class 10.9 | Class 12.9 | ||||
|---|---|---|---|---|---|---|---|---|
| Dry | Oiled | Dry | Oiled | Dry | Oiled | Dry | Oiled | |
| M3 x 0.5 | 5 in-lb | 3 in-lb | 12 in-lb | 9 in-lb | 17 in-lb | 12 in-lb | 19 in-lb | 15 in-lb |
| M4 x 0.7 | 10 in-lb | 8 in-lb | 27 in-lb | 20 in-lb | 39 in-lb | 29 in-lb | 45 in-lb | 34 in-lb |
| M5 x 0.8 | 21 in-lb | 16 in-lb | 55 in-lb | 41 in-lb | 78 in-lb | 59 in-lb | 91 in-lb | 69 in-lb |
| M6 x 1 | 36 in-lb | 27 in-lb | 93 in-lb | 70 in-lb | 11 ft-lb | 100 in-lb | 13 ft-lb | 116 in-lb |
| M8 x 1.25 | 87 in-lb | 66 in-lb | 19 ft-lb | 14 ft-lb | 27 ft-lb | 20 ft-lb | 31 ft-lb | 24 ft-lb |
| M10 x 1.5 | 14 ft-lb | 11 ft-lb | 37 ft-lb | 28 ft-lb | 53 ft-lb | 40 ft-lb | 62 ft-lb | 47 ft-lb |
| M12 x 1.75 | 25 ft-lb | 19 ft-lb | 65 ft-lb | 49 ft-lb | 93 ft-lb | 70 ft-lb | 109 ft-lb | 81 ft-lb |
| M14 x 2 | 40 ft-lb | 30 ft-lb | 103 ft-lb | 77 ft-lb | 148 ft-lb | 111 ft-lb | 173 ft-lb | 130 ft-lb |
| M16 x 2 | 63 ft-lb | 47 ft-lb | 161 ft-lb | 121 ft-lb | 231 ft-lb | 173 ft-lb | 270 ft-lb | 202 ft-lb |
| M20 x 2.5 | 122 ft-lb | 91 ft-lb | 325 ft-lb | 244 ft-lb | 450 ft-lb | 337 ft-lb | 526 ft-lb | 394 ft-lb |
| M24 x 3 | 211 ft-lb | 158 ft-lb | 562 ft-lb | 422 ft-lb | 778 ft-lb | 583 ft-lb | 909 ft-lb | 682 ft-lb |
| M30 x 3.5 | 419 ft-lb | 314 ft-lb | 1,117 ft-lb | 838 ft-lb | 1,545 ft-lb | 1,159 ft-lb | 1,806 ft-lb | 1,355 ft-lb |
Metric bolt torque chart (N·m)
| Size | Class 4.6 | Class 8.8 | Class 10.9 | Class 12.9 | ||||
|---|---|---|---|---|---|---|---|---|
| Dry | Oiled | Dry | Oiled | Dry | Oiled | Dry | Oiled | |
| M3 x 0.5 | 0.5 N·m | 0.4 N·m | 1.3 N·m | 1.0 N·m | 1.9 N·m | 1.4 N·m | 2.2 N·m | 1.6 N·m |
| M4 x 0.7 | 1.2 N·m | 0.9 N·m | 3.1 N·m | 2.3 N·m | 4.4 N·m | 3.3 N·m | 5.1 N·m | 3.8 N·m |
| M5 x 0.8 | 2.4 N·m | 1.8 N·m | 6.2 N·m | 4.6 N·m | 8.8 N·m | 6.6 N·m | 10 N·m | 7.7 N·m |
| M6 x 1 | 4.1 N·m | 3.1 N·m | 10 N·m | 7.9 N·m | 15 N·m | 11 N·m | 18 N·m | 13 N·m |
| M8 x 1.25 | 9.9 N·m | 7.4 N·m | 25 N·m | 19 N·m | 36 N·m | 27 N·m | 43 N·m | 32 N·m |
| M10 x 1.5 | 20 N·m | 15 N·m | 50 N·m | 38 N·m | 72 N·m | 54 N·m | 84 N·m | 63 N·m |
| M12 x 1.75 | 34 N·m | 26 N·m | 88 N·m | 66 N·m | 126 N·m | 94 N·m | 147 N·m | 110 N·m |
| M14 x 2 | 54 N·m | 41 N·m | 140 N·m | 105 N·m | 200 N·m | 150 N·m | 234 N·m | 176 N·m |
| M16 x 2 | 85 N·m | 64 N·m | 219 N·m | 164 N·m | 313 N·m | 235 N·m | 365 N·m | 274 N·m |
| M20 x 2.5 | 165 N·m | 124 N·m | 441 N·m | 331 N·m | 610 N·m | 458 N·m | 713 N·m | 535 N·m |
| M24 x 3 | 286 N·m | 214 N·m | 762 N·m | 572 N·m | 1,055 N·m | 791 N·m | 1,233 N·m | 925 N·m |
| M30 x 3.5 | 568 N·m | 426 N·m | 1,515 N·m | 1,136 N·m | 2,095 N·m | 1,572 N·m | 2,449 N·m | 1,837 N·m |
Calculated with T = K × D × F, where F is 75% of the bolt’s proof load1 and K is the nut factor for each condition. Real preload from a torque wrench scatters by about ±25%3. When the equipment maker gives a torque, use theirs. How these numbers are made.
How to read the chart
Read across from the size to the property class stamped on the head, then choose Dry or Oiled. The first table is in ft-lb and in-lb. The second gives the same values in N·m, the unit most metric service data uses. Sizes up to M6 in class 8.8 are under 10 ft-lb, so they are shown in in-lb. An M6 8.8 bolt is 93 in-lb (10 N·m) dry.
The size pages add the common fine pitch, such as M12 x 1.25, along with zinc-plated, anti-seize and moly values. Fine threads have a larger stress area, so on the same basis they carry 5% to 13% more clamp load than coarse threads.
Between classes, torque scales with proof stress. Class 8.8 is 580 MPa up to M16 and 600 MPa above, against 830 MPa for 10.9 and 970 MPa for 12.9 2. As a result, 12.9 takes about 17% more torque than 10.9 in every size. Class 4.6, at 225 MPa, takes well under half of what 8.8 does.
Why metric charts disagree
Metric charts spread more widely than inch charts, because their authors pick different targets:
- Clamp basis. This site uses 75% of proof load, the basis Fastenal gives for standard bolts 1. Charts that use 85% of proof come out about 13% higher. Bolt Science describes a different approach, targeting 90% of yield as a combined direct and torsional stress 4. Charts based on friction-coefficient methods (VDI 2230 style) also differ. For one M12 8.8 bolt, published values run from about 74 to 100 N·m. This chart gives 88 N·m.
- Friction coefficient or nut factor. A friction coefficient μ is not the same thing as K. NASA’s table gives K 0.133 for μ 0.10 on both thread and underhead, and K 0.189 for μ 0.15 3. A chart that says “μ 0.10” is close to this site’s oiled column, not the dry one.
- Unlabeled lubrication. Some charts print lightly oiled values with no label, and some label dry-K values as oiled. Check the stated condition before you compare.
Whatever the basis, torque-controlled preload scatters by about ±25% 3, and by up to 35% on dry or as-received threads 5.
When not to use this chart
- The equipment maker gives a value. The maker’s value accounts for the joint, the gasket and the material it clamps. This chart does not, so use the maker’s number.
- Structural bolting. ISO 898-1 notes that the 8.8 values for M16 and smaller do not apply to structural bolting 2.
- Stainless or non-ferrous bolts. ISO 898-1 covers carbon steel and alloy steel bolts only 2.
- A weaker nut or a soft tapped hole. The values assume the nut is at least as strong as the bolt 1.
Sources
- 1
- 2
- 3
- 4Bolt Science Ltd, Bolt Science, Methods of Tightening Threaded FastenersChecked 21 Oct 2026
- 5
Spotted a value that doesn’t match its source? Report an error
Related
- SAE chartSAE bolt torque chart for Grade 2, 5 and 8 from 1/4 in to 1 in, dry and lubricated, calculated from SAE J429 proof loads with the nut factor shown.
- Class 8.8Class 8.8 bolt torque from M3 to M30, dry, zinc-plated and lubricated, with the ISO 898-1 proof stress step from 580 MPa to 600 MPa above M16.
- Class 10.9Class 10.9 bolt torque from M3 to M30, dry, zinc-plated and lubricated, with ISO 898-1 strength (830 MPa proof) and how it compares with 8.8 and 12.9.
- Bolt torque calculatorBolt torque calculator for SAE and metric bolts by size, thread, grade and lubrication, using T = K × D × F with the proof loads from SAE J429 and ISO 898-1.