Bolt Torque Calculator
Find your bolt size below. Each torque is for the finish, class, material and head chosen above.
† Fine-pitch rows: coarse torque × 1.1, an unverified value (no published source). K: friction factor for the thread and bearing surface. Dry about 0.20, lubricated lower. The base tables assume K = 0.20 (dry).
| Bolt Size | Threads per inch | Torque (ft·lb) | Torque (N·m) | K used |
|---|
Terms
- Size system
- Inch sizes such as 1/2"-13, or metric sizes such as M12×1.75.
- Threads per inch, pitch
- Inch bolts count threads per inch. Metric bolts give the distance between threads in mm.
- Fine pitch (†)
- The finer thread for a size. Its torque here is the coarse value × 1.1, an unverified value.
- Finish
- The bolt's surface or lubricant. It sets K.
- K
- Friction factor for the thread and bearing surface. Dry about 0.20, lubricated lower. A lower K needs less torque for the same clamp.
- Property class
- The strength marking on metric bolts, such as 8.8, 10.9 or 12.9. Not the same as SAE grades 2, 5 and 8.
- Grade unknown
- The inch table names no bolt grade, so its values are unverified.
- Threads into
- What the bolt tightens into: a nut, or a tapped hole in a plate.
- Head type
- Hex, socket cap, pancake, countersunk or flanged. Pancake and countersunk heads get a lower torque here.
- ft·lb, N·m
- Foot-pounds and newton-meters, the two torque units shown.