Torque Calculator
Torque is force times lever arm: τ = F × r × sin θ. Enter the force, the distance from the pivot, and the angle between them — results come back in N·m, ft-lb, and in-lb.
Example: with Force 200 · Force unit newtons (N) · Lever arm length (r) 0.25 · Length unit meters (m) · Angle between force and lever (degrees) 90 → Torque: 50.00 N·m.
Computed by the calculator below using its default values. Change any input to see your own numbers.
🔧 Hit exact specs with a torque wrench
Check it outHow to calculate torque
Torque measures twisting effort: τ = F × r × sin θ, where F is the force, r is the lever-arm length from the pivot, and θ is the angle between them. Pushing 200 N on a 0.25 m wrench at 90° gives τ = 200 × 0.25 × 1 = 50 N·m, about 36.9 ft-lb. Only the perpendicular component of the force twists, so the same push at 30° delivers just 25 N·m.
The lever arm is why cheater bars work: doubling r to 0.5 m halves the force needed for the same torque. To convert units, 1 N·m = 0.73756 ft-lb and 1 ft-lb = 1.35582 N·m. Net torque about a pivot is the sum of every torque with its sign — counterclockwise positive, clockwise negative — and when that sum is zero the object is in rotational equilibrium, which is exactly the see-saw balance condition.
How it’s calculated
Torque τ = F × r × sin θ, computed in SI after converting force (1 lbf = 4.4482216152605 N) and length (1 ft = 0.3048 m, 1 in = 0.0254 m, 1 cm = 0.01 m). Output conversions: 1 N·m = 0.7375621 ft·lbf and 1 ft·lbf = 12 in·lbf. θ is the angle between the force and the lever arm; 90° (perpendicular) gives maximum torque.
Results update as you type and are estimates, not professional advice — verify important decisions with a qualified professional.
Common mistakes
- Ignoring the angle — only the force component perpendicular to the lever twists; pull straight along the handle (0°) and torque is zero.
- Mixing units — a 40 ft-lb spec is 54.2 N·m; torque a bolt with the wrong unit and you are off by roughly a third.
- Measuring r to the middle of your hand instead of the point where the force actually acts on the lever.
Frequently asked questions
How do you calculate torque?
Multiply force by lever-arm length and by the sine of the angle between them: τ = F × r × sin θ. A 100 N force applied perpendicular at 0.5 m gives 50 N·m.
What is the equation for torque in ft-lb?
Same equation with pounds-force and feet: 50 lbf perpendicular on a 1.5 ft breaker bar is 75 ft-lb (about 101.7 N·m).
How do I convert N·m to ft-lb?
Multiply N·m by 0.73756, or divide by 1.35582. A 100 N·m spec is 73.8 ft-lb.
What is net torque?
The signed sum of all torques about the same pivot, with counterclockwise counted positive. Equal 20 N·m twists in opposite directions give zero net torque — rotational equilibrium.