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Torque Calculator

Result

50.000N·m

Result: 50.000 N·m

Torque is force times lever arm: a 100 N pull on a 0.5 m wrench gives 50 N·m. Doubling the length of the wrench doubles the torque, which is why a breaker bar loosens a bolt that a short spanner will not. This calculator assumes the force pulls at a right angle to the arm.

The numbers at a glance

Held fixed: Force (N) 100.000 N.

Lever arm (m) (m)Result (N·m)
0.20020.000
0.40040.000
0.500Your value50.000
0.60060.000
0.80080.000
1.000100.000

Worked examples

How it's calculated

τ = F × r

  1. StepMeasure the force in newtons — one kilogram of weight pushes with about 9.81 N.
  2. StepMeasure the lever arm from the pivot to where the force acts, in metres.
  3. StepMultiply the two; the answer is in newton-metres.
  4. ResultPull at a right angle to the arm, or the real torque is lower.

Reference table

Force, lever armWhat that feels likeTorque
9.81, 1.5One kilogram hanging 1.5 m out14.715
12.5, 0.8A light pull on a door handle10
100, 0.5One hand on a 50 cm wrench50
200, 0.3Both hands on a short spanner60
50, 2A modest pull on a long breaker bar100

Questions

How do I calculate torque?

Multiply the force by the lever-arm length: τ = F × r. Newtons times metres gives newton-metres. A 100 N force on a 0.5 m wrench gives 50 N·m.

What is the lever arm?

The lever arm is the perpendicular distance from the pivot to the line along which the force acts. A longer lever arm produces more torque for the same force, which is why a longer wrench loosens a stubborn bolt more easily.

Does the angle of the force matter?

Yes, and this calculator assumes the force pulls at a right angle to the arm — the angle that gives the most torque. In general the torque is F × r × sin θ, so a force pulling along the arm produces none at all.

What is the difference between torque and force?

Force is a straight-line push or pull measured in newtons, while torque is the rotational effect that force produces, measured in newton-metres. The same force creates more torque when applied further from the pivot.

What units should I use?

Newtons for the force and metres for the lever arm, which gives newton-metres. If your lever arm is in centimetres, divide by 100 first. One newton-metre is the torque from a 1 N force on a 1 m lever arm.

Sources and last check

  1. openstax.org

Information, not professional advice.