How to use the torque converter
- Enter the torque in Value, for example the figure from a service manual.
- In From, choose the unit printed in that source, such as N·m or lbf·in.
- In To, choose the unit your torque wrench or datasheet uses.
- Read the answer, then check the table for every other unit. The swap button reverses the direction.
What it does and when to use it
Torque specs travel between countries and industries. A European car manual gives wheel nut torque in N·m, while an American click wrench is marked in lbf·ft. Bicycle parts and small engine covers use lbf·in or N·cm. Hobby servos and small DC motors are rated in kg·cm or oz·in. This tool converts between all of those, plus kN·m for large machinery and the CGS dyn·cm.
Torque is force times the length of the lever arm. If you have only the force at the end of a handle, convert it with the force converter first and multiply by the arm length. To estimate engine output from torque and speed, use power (W) = torque (N·m) × rpm × 2π ÷ 60, then the power converter for horsepower.
How it works
Every unit is stored as a number of newton-metres. Your value is multiplied by the “from” factor and divided by the “to” factor. The factors are exact, built from the 1959 pound and foot and standard gravity (9.80665 m/s²):
| Unit | Newton-metres |
|---|---|
| lbf·ft | 1.3558179483314004 (4.4482216152605 N × 0.3048 m) |
| lbf·in | 0.1129848290276167 (lbf·ft ÷ 12) |
| ozf·in | 0.00706155181422604 (lbf·in ÷ 16) |
| kgf·m | 9.80665 |
| kgf·cm | 0.0980665 |
| N·cm | 0.01 |
| dyn·cm | 0.0000001 |
Worked examples
Car or motorbike spec. 100 N·m = 73.7562149277 lbf·ft. The same row in the table reads 885.074579133 lbf·in and 10.1971621298 kgf·m.
Bicycle stem bolts. A part marked 25 lbf·in is 2.82462072569 N·m, which most metric bike wrenches would set as 2.8 N·m. In lbf·ft it is only 2.08333333333, which shows how easy a ×12 slip would be.
Hobby servo. A 10 kg·cm servo delivers 138.873865943 ozf·in (0.980665 N·m). Use this to compare a servo listed in oz·in with one listed in kg·cm.
Limits and tips
- The tool converts units only. It does not know thread sizes, lubrication or tightening sequences; follow the maker’s specification.
- Results show 12 significant digits. Round to what your wrench can actually set, usually whole N·m or lbf·ft.
- “kg·cm” and “kgf·cm” are the same unit in servo and motor listings. The kilogram there is a force, not a mass.
- Using a crow’s-foot or extension changes the effective arm length, so the wrench setting must be corrected. Convert the extra length with the length converter if it is given in the other system.
Frequently asked questions
How do I convert N·m to ft-lb?
Are inch-pounds and foot-pounds easy to mix up?
What does kg·cm mean on a servo or motor?
Is a newton-metre the same as a joule?
Sources
- NIST Guide to the SI, Appendix B.8: Factors for units listed alphabetically — NIST, accessed 2026-10-08
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