Torque Calculator

Turning force, in newton-metres and pound-feet.

Turning force, in newton-metres and pound-feet. τ = rF sin θ, maximal when the force is perpendicular to the arm.

Written and maintained by Mohit PatelLast checked August 4, 2026How we build these

Force

Lever arm

Angle to the arm

Torque (N·m)

22.127 lb·ft

Torque30 N·m

In pound-feet22.127

Effective force100 N

With half the lever arm15 N·m

Force needed at 1 m30 N

τ = rF sin θ, maximal when the force is perpendicular to the arm. The lever arm matters as much as the force: halving it to 0.15 m halves the torque to 15 N·m. Pulling along the arm rather than across it achieves nothing at all, since sin 0° is zero — which is why a spanner is turned, not tugged.

How the Torque Calculator works

τ = rF sin θ, maximal when the force is perpendicular to the arm. The lever arm matters as much as the force (halving it halves the torque) and pulling along the arm rather than across it achieves nothing at all, which is why a spanner is turned rather than tugged.

Also known as: torque formula · newton meters to pound feet · torque wrench calculator · how to calculate torque

Where to go next

The Torque question rarely arrives on its own. These are the ones that usually come with it:

Force Calculator — F = ma, in newtons, kilograms-force and pounds-force.
Work Calculator — W = Fd cos θ, including the case that comes out zero.
Power Calculator — Watts, kilowatts and horsepower, with a running cost.
Speed Distance Time Calculator — Any one of the three from the other two, in four units.

Sources

Frequently asked questions

How do I calculate torque?

Multiply the force by the lever arm length, times the sine of the angle between them. 100 N on a 0.3 m arm, applied perpendicular, gives 30 N·m.

How do I convert newton-metres to pound-feet?

Multiply by 0.7376. So 30 N·m is 22.13 lb·ft.

Why does the lever arm matter so much?

Because torque is proportional to it. Doubling the length of a spanner halves the force needed for the same torque, which is the entire reason breaker bars exist.

Does the angle really matter?

Yes. Only the perpendicular component turns anything, so a force at 30° to the arm delivers half the torque of the same force applied at 90°.

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