To convert inch-pounds to foot-pounds (in·lb to ft·lb), multiply by 0.083333. 1 inch-pound equals 0.083333 ft·lb.
| inch-pounds | foot-pounds |
|---|---|
| 1 inch-pound | 0.083333 ft·lb |
| 2 inch-pounds | 0.16667 ft·lb |
| 5 inch-pounds | 0.41667 ft·lb |
| 10 inch-pounds | 0.83333 ft·lb |
| 25 inch-pounds | 2.0833333 ft·lb |
| 50 inch-pounds | 4.1666667 ft·lb |
| 100 inch-pounds | 8.3333333 ft·lb |
| 250 inch-pounds | 20.833333 ft·lb |
| 500 inch-pounds | 41.666667 ft·lb |
| 1000 inch-pounds | 83.333333 ft·lb |
Definition: The turning force from one pound of force applied at the end of a one-inch lever arm - twelve times smaller than a foot-pound, since a foot is twelve inches.
History: It exists for the same reason a ruler has both inches and feet: foot-pounds give clumsy, awkward numbers for small torque values, so mechanics and engineers working on delicate components switched to a shorter lever-arm unit that reads in comfortable whole numbers instead.
Current use: Small fasteners, electronics, bicycle components, and precision assembly. Mixing this up with foot-pounds is a genuinely common and expensive mistake - setting a wrench to the wrong one applies 12 times the intended torque.
Definition: The turning force from one pound of force applied at the end of a one-foot lever arm.
History: British physicist Arthur Mason Worthington actually proposed calling this "pound-foot" in his 1900 book Dynamics of Rotation, specifically to avoid confusing it with the identically-named foot-pound unit of energy - a real, separate quantity. The distinction never really caught on in everyday use: garages, manuals, and torque wrenches worldwide just say "ft-lbs" for both, and mechanics learn to tell them apart from context instead.
Current use: The dominant torque unit in the US - car manuals, torque wrenches, and workshop specs almost universally use ft-lb for anything beyond small fasteners.
The factor is 0.0833333, which is derived rather than defined, so any decimal you see has been rounded somewhere.
No simple round multiplier is close enough to be useful, so this is one to look up rather than estimate. The exact factor is 0.0833333.
Going the other way, one foot-pound is 12 in·lb, which is usually the easier direction to work in. Because the forward factor is small, watch the decimal place rather than the digits: a factor-of-ten slip is the common error, not a rounding one.
To anchor the scale: 20 inch-pounds is about 1.67 ft·lb.