M10 bolt torque specifications (8.8, 10.9, 12.9)
An M10 x 1.5 class 8.8 bolt takes 37 ft-lb (50 N·m) dry, and class 10.9 takes 53 ft-lb (72 N·m). Both are for plain steel, dry threads (K 0.20) tightened to a clamp load of 75% of proof load.
Contents13 sections
Key takeaways
- Class 8.8 dry: 37 ft-lb (50 N·m); class 10.9 dry: 53 ft-lb (72 N·m).
- Wrench: 16 mm for ISO 4014/4017 heads, 17 mm for older DIN 931/933 heads 1.
- M10 x 1.25 fine adds only about 5.5% clamp load, the smallest coarse-to-fine gain in this chart.
- An M10 class 8.8 takes about 21% more torque than a 3/8-16 Grade 5.
Quick facts
| Coarse thread | M10 x 1.5 (58.0 mm²) |
|---|---|
| Fine thread | M10 x 1.25 (61.2 mm²) |
| Wrench, ISO 4014/4017 | 16 mm |
| Wrench, DIN 931/933 | 17 mm |
M10 bolt specifications
| Thread | Pitch | Tensile stress area |
|---|---|---|
| M10 x 1.5 (coarse) | 1.5 mm pitch | 58.0 mm² |
| M10 x 1.25 (fine) | 1.25 mm pitch | 61.2 mm² |
| Wrench, ISO 4014/4017 | 16 mm1 | |
| Wrench, older DIN 931/933 | 17 mm | |
Stress areas from ISO 898-1 Table 42.
M10 torque by grade
| Grade | Plain, dry K 0.201 | Lubricated K 0.151 | Clamp load |
|---|---|---|---|
| Class 4.6 | 14 ft-lb20 N·m | 11 ft-lb15 N·m | 9.8 kN |
| Class 8.8 | 37 ft-lb50 N·m | 28 ft-lb38 N·m | 25.2 kN |
| Class 10.9 | 53 ft-lb72 N·m | 40 ft-lb54 N·m | 36.1 kN |
| Class 12.9 | 62 ft-lb84 N·m | 47 ft-lb63 N·m | 42.2 kN |
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.
M10 4.6 torque
Proof 225 MPa · yield 240 MPa · tensile 400 MPa2. Clamp load at 75% of proof: 9.8 kN (M10 x 1.5).
| Condition | K | M10 x 1.5 | M10 x 1.25 |
|---|---|---|---|
| Plain steel, dryAs-received black or plain finish, clean threads, no lubricant | 0.201 | 14 ft-lb20 N·m | 15 ft-lb21 N·m |
| Zinc-plated, dryClean zinc-plated threads, no added lubricant | 0.181 | 13 ft-lb18 N·m | 14 ft-lb19 N·m |
| Lubricated (oil or grease)Light oil or grease on the threads and under the nut or head | 0.151 | 11 ft-lb15 N·m | 11 ft-lb15 N·m |
| Copper or metal-free anti-seizeLoctite C5-A copper or N-7000 metal-free anti-seize | 0.164 | 12 ft-lb16 N·m | 12 ft-lb17 N·m |
| Moly pasteMolybdenum disulfide paste | 0.115 | 95 in-lb11 N·m | 101 in-lb11 N·m |
M10 8.8 torque
Proof 580 MPa · yield 640 MPa · tensile 800 MPa2. Clamp load at 75% of proof: 25.2 kN (M10 x 1.5).
| Condition | K | M10 x 1.5 | M10 x 1.25 |
|---|---|---|---|
| Plain steel, dryAs-received black or plain finish, clean threads, no lubricant | 0.201 | 37 ft-lb50 N·m | 39 ft-lb53 N·m |
| Zinc-plated, dryClean zinc-plated threads, no added lubricant | 0.181 | 33 ft-lb45 N·m | 35 ft-lb48 N·m |
| Lubricated (oil or grease)Light oil or grease on the threads and under the nut or head | 0.151 | 28 ft-lb38 N·m | 29 ft-lb40 N·m |
| Copper or metal-free anti-seizeLoctite C5-A copper or N-7000 metal-free anti-seize | 0.164 | 30 ft-lb40 N·m | 31 ft-lb43 N·m |
| Moly pasteMolybdenum disulfide paste | 0.115 | 20 ft-lb28 N·m | 22 ft-lb29 N·m |
M10 10.9 torque
Proof 830 MPa · yield 940 MPa · tensile 1040 MPa2. Clamp load at 75% of proof: 36.1 kN (M10 x 1.5).
| Condition | K | M10 x 1.5 | M10 x 1.25 |
|---|---|---|---|
| Plain steel, dryAs-received black or plain finish, clean threads, no lubricant | 0.201 | 53 ft-lb72 N·m | 56 ft-lb76 N·m |
| Zinc-plated, dryClean zinc-plated threads, no added lubricant | 0.181 | 48 ft-lb65 N·m | 51 ft-lb69 N·m |
| Lubricated (oil or grease)Light oil or grease on the threads and under the nut or head | 0.151 | 40 ft-lb54 N·m | 42 ft-lb57 N·m |
| Copper or metal-free anti-seizeLoctite C5-A copper or N-7000 metal-free anti-seize | 0.164 | 43 ft-lb58 N·m | 45 ft-lb61 N·m |
| Moly pasteMolybdenum disulfide paste | 0.115 | 29 ft-lb40 N·m | 31 ft-lb42 N·m |
M10 12.9 torque
Proof 970 MPa · yield 1100 MPa · tensile 1220 MPa2. Clamp load at 75% of proof: 42.2 kN (M10 x 1.5).
| Condition | K | M10 x 1.5 | M10 x 1.25 |
|---|---|---|---|
| Plain steel, dryAs-received black or plain finish, clean threads, no lubricant | 0.201 | 62 ft-lb84 N·m | 66 ft-lb89 N·m |
| Zinc-plated, dryClean zinc-plated threads, no added lubricant | 0.181 | 56 ft-lb76 N·m | 59 ft-lb80 N·m |
| Lubricated (oil or grease)Light oil or grease on the threads and under the nut or head | 0.151 | 47 ft-lb63 N·m | 49 ft-lb67 N·m |
| Copper or metal-free anti-seizeLoctite C5-A copper or N-7000 metal-free anti-seize | 0.164 | 50 ft-lb68 N·m | 53 ft-lb71 N·m |
| Moly pasteMolybdenum disulfide paste | 0.115 | 34 ft-lb46 N·m | 36 ft-lb49 N·m |
Coarse or fine pitch
M10 x 1.5 coarse has 58.0 mm² of stress area 2; M10 x 1.25 fine has 61.2 mm² 1. The fine thread carries only about 5.5% more clamp load, the smallest gain of any size in this chart: 26.6 kN against 25.2 kN in class 8.8, and 39 ft-lb dry against 37 ft-lb. The ISO 262 table also lists M10 x 1 6; by the ISO stress-area formula it has about 64.5 mm², roughly 11% more than the coarse thread, and is not in the tables above.
Wrench size: ISO or DIN
M10 is the first size in this chart where the two hex standards disagree. An ISO 4014/4017 head is 16 mm across the flats, while an older DIN 931/933 head is 17 mm 1. Nuts follow the same split: Fastenal lists DIN 934 M10 nuts at 17 mm with the ISO 4032 size, 16 mm, in brackets 1. Measure or test-fit the head before choosing between a 16 mm and a 17 mm socket. The socket size chart lists every size.
Proof load and clamp load
ISO 898-1 lists the M10 coarse proof load as 33,700 N for class 8.8 and 48,100 N for 10.9 2. The chart clamps at 75% of those: 25.2 kN (about 5,670 lbf) and 36.1 kN (about 8,120 lbf).
Next to 3/8 in (9.53 mm), M10 is the larger bolt. Calculated the same way, an M10 class 8.8 takes about 21% more torque than a 3/8-16 Grade 5 and clamps about 15% more.
Which class you have
The class is marked on the head with the maker’s mark 2; see the bolt grades page. Class 10.9 is about 43% above 8.8 at this size, and 12.9 dry is 62 ft-lb (84 N·m). ISO 898-1 also defines class 9.8 for sizes up to M16 2, which this chart does not cover.
When the chart does not apply
A 10 mm spark plug is not an M10 bolt. NGK gives 7.2 to 8.7 ft-lb for a flat-seat 10 mm plug in an aluminum head 7, less than a quarter of the 8.8 bolt value; see spark plug torque. With copper anti-seize (K 0.16) 4 an M10 class 8.8 takes 30 ft-lb, not 37; see dry vs lubricated torque.
Sources
- 1
- 2
- 3
- 4
- 5Henkel Corporation (LOCTITE), LOCTITE LB 8012 Moly Paste TDS, April 2015Checked 21 Oct 2026
- 6Wikipedia, Wikipedia: ISO metric screw thread (ISO 262 selected sizes table)Checked 21 Oct 2026
- 7NGK Spark Plugs (Niterra), How do I install spark plugs correctly?Checked 21 Oct 2026
Spotted a value that doesn’t match its source? Report an error
Related
- M8M8 x 1.25 bolt torque: 19 ft-lb (25 N·m) for class 8.8 and 27 ft-lb (36 N·m) for 10.9 dry, with 12.9, M8 x 1 fine, zinc and oiled values.
- M12M12 x 1.75 bolt torque: 65 ft-lb (88 N·m) for class 8.8 and 93 ft-lb (126 N·m) for 10.9 dry, plus 12.9, M12 x 1.25 fine and the 18 vs 19 mm wrench.
- Socket size chartSocket sizes for inch hex cap screws, heavy hex structural bolts and metric bolts, including M10, M12, M14 and M22, where ISO and DIN heads differ.
- 3/8 in3/8-16 Grade 5 bolt torque is 31 ft-lb dry and Grade 8 is 44 ft-lb. Charts for 3/8-16 and 3/8-24 in Grade 2, 5 and 8, dry, zinc-plated and oiled.
- 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.
- Dry vs lubricated torqueWhy oiled bolts need less torque than dry ones for the same clamp load, with nut factor K values from Fastenal, NASA and Henkel for oil, zinc, anti-seize and moly.