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Inch-Pounds to Foot-Pounds

1 Inch-Pound Force (in·lbf) = 0.0833333Foot-Pound Force (ft·lbf)

By KAMP Inc. / UnitOwl · Last reviewed:

Result
0.0833333 ft·lbf
1 in·lbf = 0.0833333 ft·lbf
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How Many Foot-Pounds in an Inch-Pound?

One inch-pound equals exactly 1/12 of a foot-pound, or approximately 0.08333 ft-lbs. To convert inch-pounds to foot-pounds, divide the in-lbs value by 12. This is a simple, exact conversion within the imperial system, needed whenever you have a torque specification in one unit but your wrench reads in the other. For example, small fastener specs are often given in inch-pounds, but your torque wrench might only show foot-pounds. The conversion is also useful when comparing torque values across different specifications or tools. Since most automotive torque wrenches start at around 10 ft-lbs (120 in-lbs), understanding this conversion helps you decide whether you need a standard torque wrench or a smaller inch-pound torque wrench for the job. In practice, the unit math is easy but the tool-choice decision is the real reason this conversion matters. If the converted value lands near the bottom of a wrench range, the safer move is usually to switch to an inch-pound tool instead of trusting a larger wrench at its least accurate end. Small fasteners punish that kind of shortcut quickly.

How to Convert Inch-Pound Force to Foot-Pound Force

  1. Start with your torque value in inch-pounds (in-lbs).
  2. Divide the in-lbs value by 12 to get foot-pounds (ft-lbs).
  3. The result is your torque in foot-pounds.
  4. This conversion is exact — no rounding error involved.
  5. For the reverse direction, multiply ft-lbs by 12 to get in-lbs.

Real-World Examples

A small engine manual lists a bolt at 96 in-lbs. What is that in ft-lbs?
96 / 12 = 8 ft-lbs. This is at the very bottom of most standard torque wrenches, so an in-lb wrench may be more accurate.
An electronics chassis screw is specified at 30 in-lbs.
30 / 12 = 2.5 ft-lbs. Far too low for a standard torque wrench. Use a torque screwdriver or in-lb torque wrench.
A thermostat housing requires 120 in-lbs.
120 / 12 = 10 ft-lbs. Right at the threshold where a standard 10-150 ft-lbs torque wrench begins.
A drone motor mount calls for 48 in-lbs.
48 / 12 = 4 ft-lbs. Use a precision torque tool — standard automotive wrenches are not accurate at this low end.

Quick Reference

Inch-Pound Force (in·lbf)Foot-Pound Force (ft·lbf)
10.0833333
20.166667
50.416667
100.833333
252.08333
504.16667
1008.33333
50041.6667
1,00083.3333

History of Inch-Pound Force and Foot-Pound Force

The inch-pound and foot-pound share a common heritage in the British imperial system. Both are torque units defined by a force of one pound acting at a distance of one inch or one foot, respectively. The 12:1 ratio mirrors the 12-inch-to-foot relationship that has been standard since medieval England. The inch-pound became particularly important in the 20th century as precision manufacturing, aviation, and electronics demanded torque control at scales where foot-pounds were too coarse a unit.

Common Mistakes to Avoid

  • Multiplying by 12 instead of dividing. This converts ft-lbs to in-lbs (the opposite direction). If your result is larger than the in-lbs starting value, you went the wrong way.
  • Assuming your standard torque wrench is accurate at low ft-lbs values. Most 1/2-inch drive torque wrenches rated for 10-150 ft-lbs are unreliable below about 20% of their range (20-30 ft-lbs). For converted values under 15 ft-lbs, use a dedicated inch-pound torque wrench.
  • Ignoring the distinction between the two units entirely. A specification of 25 in-lbs (2.1 ft-lbs) versus 25 ft-lbs (300 in-lbs) is a 12x difference. On a small aluminum bolt, this mistake destroys the thread instantly.
  • Rounding a low converted result and then using a coarse wrench scale as if it were precise. A target of 2.5 ft-lbs may be mathematically correct, but many standard click wrenches cannot set that value accurately. The better solution is usually to stay in inch-pounds with an appropriate tool.
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Frequently Asked Questions

Why do some specifications use inch-pounds instead of foot-pounds?
Inch-pounds are used for low-torque applications where foot-pounds would give inconveniently small fractions. A specification of 2.5 ft-lbs is clearer as 30 in-lbs. In-lb specifications are common in aviation, electronics, bicycle, and small engine work.
At what point should I switch from an in-lb wrench to a ft-lbs wrench?
The transition typically happens around 100-150 in-lbs (8-12.5 ft-lbs). Below this range, an inch-pound torque wrench or torque screwdriver gives better accuracy. Above it, a standard foot-pound torque wrench is appropriate.
Can I convert Nm directly to in-lbs?
Yes. Multiply Nm by 8.8507 to get inch-pounds. Or convert Nm to ft-lbs first (multiply by 0.7376) and then multiply by 12. Both methods give the same result.
When is it acceptable to work in converted ft-lbs instead of staying in in-lbs?
It is acceptable when the converted value sits comfortably in the accurate middle of your foot-pound wrench range. If the result is only a few ft-lbs, or if the fastener is delicate, stay with inch-pounds so you can set the tool more precisely.
Why are so many small fastener specs written in inch-pounds?
Because inch-pounds produce clearer numbers for low torques. A fastener tightened to 36 in-lbs is easier to read and set than the same value written as 3 ft-lbs. That is why service data for aviation, electronics, bicycles, and small engines often uses in-lbs for light-duty hardware.
Quick Tip

A handy set of benchmarks: 12 in-lbs = 1 ft-lbs, 60 in-lbs = 5 ft-lbs, 120 in-lbs = 10 ft-lbs, 240 in-lbs = 20 ft-lbs. If you frequently work with both units, these multiples-of-12 benchmarks help you quickly judge whether a given spec is in the range of your available torque tools.

Torque vs. Power

Torque is the rotational force an engine produces; power is how fast it can apply that force. High torque at low RPM → strong towing. High power at high RPM → top-end speed. Multiply torque (lb·ft) × RPM ÷ 5,252 to get horsepower.

Sources & References