Torque Calculator
Enter a force and a lever-arm length to get the torque in newton-metres — the turning effect that loosens a bolt, spins a wheel, or tightens a screw.
Force times lever arm
Enter the force in newtons and the lever-arm length in metres and the calculator returns the torque (F × r) in newton-metres straight away.
Use SI units
Force in newtons and lever arm in metres give torque in newton-metres — divide a lever arm in centimetres by 100 to get metres before you start.
What is torque?
The turning effect of a force
This torque calculator turns two measurements — the force in newtons and the lever-arm length in metres — into the torque in newton-metres, the twisting effect that force has around a pivot. Torque is what makes things rotate: it is the reason a longer wrench loosens a stubborn bolt more easily, why a door is harder to push near its hinges, and how an engine delivers turning power to the wheels. It grows with both the size of the force and how far from the pivot that force is applied, so a modest push at the end of a long lever can beat a hard shove close to the centre.
Enter a force in newtons and a lever-arm length in metres to get the torque in newton-metres instantly.
Torque is simply the force multiplied by the lever-arm length, when the force is applied perpendicular to the lever arm.
τ = F × rSuppose you push with a force of 100 N at the end of a wrench whose handle is 0.5 m long. Multiply the two together — 100 × 0.5 = 50 — and you get a torque of 50 N·m. Double the handle length to 1 m and the same push delivers 100 N·m, twice the turning effect, which is exactly why mechanics reach for a longer breaker bar when a bolt will not budge.
The formula is exact, but it rests on one key assumption worth keeping in mind.
Perpendicular force and consistent units
This calculator assumes the force is applied at 90° to the lever arm, which gives the maximum torque. When the force acts at another angle θ, only the perpendicular component counts, so the torque becomes τ = F × r × sin(θ) — there is no angle input here, so use that formula separately if your force is not perpendicular. Keep your units consistent — newtons for the force and metres for the lever arm — or the newton-metres will be wrong: convert a lever arm given in centimetres to metres by dividing by 100 before you enter it.