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Foot-Pounds to Inch-Pounds

1 Foot-Pound Force (ft·lbf) = 12Inch-Pound Force (in·lbf)

By KAMP Inc. / UnitOwl · Last reviewed:

Result
12 in·lbf
1 ft·lbf = 12 in·lbf
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How Many Inch-Pounds in a Foot-Pound?

One foot-pound equals exactly 12 inch-pounds. To convert ft-lbs to in-lbs, multiply the ft-lbs value by 12. This is the simplest torque conversion — it is an exact relationship within the imperial system with no approximation. You need it when a specification is given in foot-pounds but your torque tool is calibrated in inch-pounds, or vice versa. This most often happens when transitioning between larger automotive fasteners (specified in ft-lbs) and smaller precision fasteners (specified in in-lbs) during the same project. For example, assembling a carburetor might involve both ft-lbs intake manifold bolts and in-lbs mixture screw settings. The conversion also helps you decide when a small torque tool is the better choice even if the manual uses foot-pounds. If a spec converts to a low in-lbs value that sits comfortably on a compact wrench, you will usually get a more reliable result than trying to set a large wrench near the bottom of its scale. It is one of the fastest ways to sanity-check tool choice before tightening any low-range hardware.

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

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

Real-World Examples

A valve cover bolt specification is 7 ft-lbs. What is that in in-lbs?
7 x 12 = 84 in-lbs. An inch-pound torque wrench may be more accurate at this low torque than a standard ft-lbs wrench.
A small bracket bolt calls for 3 ft-lbs.
3 x 12 = 36 in-lbs. Definitely use an inch-pound torque wrench or torque screwdriver for this.
An oil pump cover requires 9 ft-lbs.
9 x 12 = 108 in-lbs. Right at the range where either an in-lb or ft-lbs wrench could work.
A rocker arm adjustment nut needs 2 ft-lbs.
2 x 12 = 24 in-lbs. This is too low for any standard automotive torque wrench — use a dedicated in-lb tool.

Quick Reference

Foot-Pound Force (ft·lbf)Inch-Pound Force (in·lbf)
112
224
560
10120
25300
50600
1001,200

History of Foot-Pound Force and Inch-Pound Force

The foot-pound and inch-pound are both derived from the same imperial measurement tradition, with the 12:1 ratio reflecting the 12 inches in a foot. The inch-pound became a distinct practical unit as manufacturing precision increased throughout the 20th century, particularly in aviation and electronics where low-torque fasteners are common. The AN (Army-Navy) standards for aircraft fasteners, developed during World War II, were among the first to widely specify torques in inch-pounds, recognizing that foot-pounds were too coarse for small aircraft hardware.

Common Mistakes to Avoid

  • Dividing by 12 instead of multiplying when going from ft-lbs to in-lbs. This gives a number 144 times too small. If your result is a fraction of the starting value, you went the wrong direction.
  • Forgetting to check which unit a specification uses. A label that says "25" could mean 25 ft-lbs (300 in-lbs) or 25 in-lbs (2.08 ft-lbs). The difference is more than 14x. Always confirm the unit.
  • Trying to use a 1/2-inch drive torque wrench for in-lb level torques. These wrenches are designed for 20-250 ft-lbs. At 5 ft-lbs (60 in-lbs), they have poor accuracy. Use the right tool for the range.
  • Converting correctly but then rounding so aggressively that the tool setting drifts from the published intent. A 7 ft-lbs target is 84 in-lbs, not "about 80." On light-duty fasteners, that small-looking change can noticeably alter clamp load.
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Frequently Asked Questions

Why does the 12:1 ratio exist?
Because there are exactly 12 inches in one foot. Since torque is force times distance, one pound of force at 12 inches from the pivot produces the same torque as one pound at one foot. The units are directly proportional to the distance measurement.
Is there a metric equivalent of the ft-lbs to in-lbs relationship?
The closest parallel would be Nm to Ncm (newton-centimeters), where 1 Nm = 100 Ncm. However, Ncm is rarely used in practice. The metric world typically stays in Nm and uses decimal values for small torques.
What range should my in-lb torque wrench cover?
For general use, a 20-200 in-lbs (1.7-16.7 ft-lbs) range covers most small fastener applications. Aviation and electronics work may need a 10-100 in-lbs range. For even smaller torques, a torque screwdriver with a 5-50 in-lbs range is appropriate.
When does it make sense to convert ft-lbs specs into in-lbs before starting work?
It makes sense when the project includes several low-torque fasteners, when your most accurate tool is marked in inch-pounds, or when you want a clearer worksheet for small hardware. Pre-converting and writing the in-lbs values down helps you avoid mental math during assembly.
Why do low ft-lbs specs often feel awkward on a standard wrench?
Because large click wrenches are designed for higher torque ranges, so the bottom end of the scale is less precise and harder to set cleanly. Converting to inch-pounds often reveals that the job really belongs on a smaller, more sensitive torque tool.
Quick Tip

The easy way to remember the crossover point: if the specification is 10 ft-lbs or less (120 in-lbs or less), use an inch-pound torque wrench. Above 10 ft-lbs, a standard foot-pound wrench is accurate enough. For the 8-15 ft-lbs range (96-180 in-lbs), either tool can work — use whichever one puts the target in the middle of its range for best accuracy.

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