What this calculator does
Change a torque spec from one unit to another, such as newton meters to foot-pounds for your wrench. Torque is a turning force: a push or pull applied some distance from a pivot. So its unit is always a force times a length.
The metric (SI) unit is the newton meter. US mechanics use foot-pounds for wheel nuts and engines, and inch-pounds for small fasteners. Older and Asian service manuals sometimes give kilogram-force meters. Small motors and servos are often rated in ounce-force inches.
Getting a torque spec wrong can strip a thread or leave a bolt loose. That's why this converter uses exact definitions. Enter a value and choose the two units. You get the answer, the working through newton meters, and a table of the same torque in every unit.
Where it's used
Why this math matters outside the classroom:
- Lug nuts. A wheel torque spec of 100 ft·lb is about 135.6 N·m.
- Bike parts. A 5 N·m stem bolt spec is about 44.3 in·lb on a US torque wrench.
- Engine specs. An engine making 400 N·m of torque produces about 295 lb·ft.
- Small fasteners. Electronics assemblers convert 8 ozf·in to about 0.0565 N·m.
- Inch-pounds. Students see that 1 ft·lb is 12 in·lb because the lever arm in inches is 12 times the number in feet.
Grade level and standards: Grades 6–7; Common Core State Standards for Mathematics 6.RP.A.3.d. © Copyright 2010. National Governors Association Center for Best Practices and Council of Chief State School Officers. All rights reserved.
How to use it
- Enter the torque value from your spec sheet or wrench.
- Choose the unit it's in and the unit your tool reads.
- Read the result. The table shows the same torque in all six units, which is handy when a manual and a wrench disagree.
What the inputs mean
- Torque
- The size of the torque, in the From unit.
- From
- For torque, lbf·ft means the same as ft·lb or foot-pounds. lbf·in means inch-pounds.
- To
- The unit for the answer.
Formula and method
result = value × (from-unit in N·m) ÷ (to-unit in N·m) 1 lbf·ft = 4.4482216152605 N × 0.3048 m ≈ 1.35581795 N·m 1 lbf·in = 4.4482216152605 N × 0.0254 m ≈ 0.11298483 N·m 1 kgf·m = 9.80665 N × 1 m = 9.80665 N·m 1 ozf·in = (1 lbf ÷ 16) × 0.0254 m ≈ 0.00706155 N·m
N·m is the newton meter. lbf is a pound-force, kgf a kilogram-force and ozf an ounce-force. ft, in and m are feet, inches and meters.
Each torque unit is a force unit times a length unit. Every one of those has an exact metric value. Multiplying them gives each unit's exact size in newton meters.
The converter multiplies your value by the from-unit's size in newton meters. Then it divides by the to-unit's size. Twelve inch-pounds make one foot-pound, because a foot is twelve inches.
Worked example
A wheel nut is specified at 100 N·m, but your torque wrench reads in foot-pounds.
- 1 lbf·ft = 1.3558179483 N·m.
- 100 N·m ÷ 1.3558179483 = 73.7562149277 lbf·ft.
Result: Set the wrench to about 73.8 lbf·ft (ft·lb).
Understanding the result
Rules of thumb: 1 N·m is about 0.738 ft·lb or 8.85 in·lb, and 1 ft·lb is about 1.356 N·m.
Torque wrenches are usually accurate to within a few percent. So rounding a converted value to your wrench's scale is normal practice.
Assumptions and limitations
- Gravity-based units use standard gravity, 9.80665 m/s², and the international pound and inch.
- Foot-pounds here are foot-pounds of torque (lbf·ft), not foot-pounds of energy. The two share the same units but mean different things.
- It converts sizes only. It doesn't handle which way you tighten.
- It doesn't turn torque into power. That needs the turning speed as well.
- Thread lubrication, and the torque-then-angle steps some service manuals give, are outside its scope.
Frequently asked questions
Is ft-lb the same as lb-ft?
For torque they mean the same thing: one pound-force pushing one foot from the pivot. Engineers often write lbf·ft for torque and ft·lbf for energy to keep the two ideas apart. But the size is identical.
How do I convert inch-pounds to foot-pounds?
Divide by 12. One foot-pound is the same turning effect as twelve inch-pounds, so 240 in·lb is 20 ft·lb.
Why is a newton meter of torque not called a joule?
Torque and energy share the same units, force times distance, but they describe different things. The joule is kept for energy and work. So torque is written in newton meters to avoid confusion.
How this calculator is checked
Method: Products of exact force factors (lbf, kgf, ozf from the international pound and standard gravity) and exact length factors (inch 0.0254 m, foot 0.3048 m). The calculation is covered by automated tests with known reference values and edge cases. Last updated 2026-10-18. Found a problem? Tell us.
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