Torque Calculator: Lb-Ft, N-m and Force
This torque calculator works two ways. Enter a force and the length of the lever arm, plus the angle if the push is not square to the wrench, and it returns the torque in pound-feet, pound-inches and newton-meters. Or enter engine horsepower and RPM to get the torque an engine makes at that speed, using the familiar 5,252 rule. A third mode simply converts a torque value between lb-ft, lb-in, N·m and kgf·m. It is useful for wrench settings, bolt specs, engine math and physics homework, with US units first and metric alongside.
Torque Calculator
Torque from force and lever arm, or from horsepower and RPM.
How to use the Torque Calculator
- Pick a mode: force and distance, horsepower and RPM, or convert units.
- Enter the values and choose units.
- For force and distance, set the angle (90° means a square push).
- Read the torque in all common units.
Torque formulas
ฯ = F × r × sin ฮธ. Engine torque: lb-ft = hp × 5,252 ÷ RPM. 1 lb-ft = 1.35582 N·m = 12 lb-in.
Features
- Force × distance with angle
- Torque from horsepower and RPM
- lb-ft, lb-in, N·m and kgf·m
- Converter mode
- US units first
- Copy and print
Frequently asked questions
What is the formula for torque?
Torque = force × distance × sin(angle). Pushing 50 lb at the end of a 1.5 ft wrench at 90° gives 75 lb-ft.
How do I convert lb-ft to N·m?
Multiply by 1.35582. For example, 100 lb-ft is about 135.6 N·m.
How do I get torque from horsepower?
Torque (lb-ft) = horsepower × 5,252 ÷ RPM. 300 hp at 5,000 RPM is about 315 lb-ft.
Why does 5,252 come up in engine math?
Horsepower and torque in lb-ft are equal at 5,252 RPM because one horsepower is 33,000 ft-lb per minute and 33,000 ÷ 2ฯ ≈ 5,252.
What is the difference between lb-ft and ft-lb?
For torque, people use both terms for the same unit. Strictly, ft-lb is often used for work or energy.