Divide by 12 — and it is exact
The factor is exactly 12 because a foot is exactly 12 inches, and torque is force times distance. Unlike most conversions, there is no rounding: 240 in-lb is precisely 20 ft-lb. In your head, drop the last digit and halve what is left is close enough as a sanity check, but the real rule is just ÷ 12.
Common torque values
| Inch-pounds | Foot-pounds | Newton-metres |
|---|---|---|
| 12 in-lb | 1 ft-lb | 1.36 N·m |
| 24 in-lb | 2 ft-lb | 2.71 N·m |
| 60 in-lb | 5 ft-lb | 6.78 N·m |
| 100 in-lb | 8.33 ft-lb | 11.30 N·m |
| 120 in-lb | 10 ft-lb | 13.56 N·m |
| 180 in-lb | 15 ft-lb | 20.34 N·m |
| 240 in-lb | 20 ft-lb | 27.12 N·m |
| 360 in-lb | 30 ft-lb | 40.68 N·m |
Newton-metres are the SI unit many modern wrenches also display: 1 ft-lb ≈ 1.356 N·m.
The mistake that snaps bolts
- in-lb and ft-lb are not interchangeable. A spec of 100 in-lb is 8.3 ft-lb. Read the wrong unit off a torque wrench and you apply twelve times the intended force.
- Inch-pounds are for small, precise work — electronics, small-engine bolts, delicate fasteners. Foot-pounds are for automotive and heavy assembly like lug nuts and head bolts.
- Check the wrench scale first. A typical inch-pound wrench tops out around 100–250 in-lb, well below most ft-lb specs, so it physically cannot reach a foot-pound target.
Common questions
What is the exact conversion from inch-pounds to foot-pounds?
Divide inch-pounds by 12. The ratio is exact because one foot is exactly 12 inches, so 1 ft-lb equals 12 in-lb with no rounding. To go the other way, multiply foot-pounds by 12.
Is inch-pounds the same as foot-pounds?
No. They measure the same thing, torque, but an inch-pound is one twelfth the size. A spec of 100 in-lb is only 8.3 ft-lb. Setting a wrench to 100 ft-lb when the spec was 100 in-lb over-tightens the fastener twelvefold and will likely snap it.
How do I convert 120 inch-pounds to foot-pounds?
120 divided by 12 is 10 foot-pounds. Any inch-pound figure that ends in a clean multiple of 12 converts to a whole number.
