Numeros
Categories Financial Calculators Health Calculators Math Calculators Date & Time Construction Engineering Physics Business Education Lifestyle Converters Generators
About

Torque Calculator

By

Enter any two of force, lever arm length, and torque - the third is calculated automatically.

Torque Calculator

Live
Torque =
100 lb-ft
Fill in exactly two values, and leave the one you want to solve for blank. Assumes force is applied perpendicular to the lever arm.

The formula

Torque = Force x Lever arm length (with force applied perpendicular to the arm)
Example

50 lb of force applied at a 2 ft lever arm: torque = 50 x 2 = 100 lb-ft.

Step-by-step guide

  1. Fill in any two values - force, lever arm length, or torque - and leave the third blank.
  2. Read the calculated result.

Torque and the angle of applied force

This calculator assumes force is applied exactly perpendicular to the lever arm, which gives the maximum possible torque for a given force and arm length. Applying force at any other angle produces less torque - the full formula is Torque = Force x Lever arm x sin(angle), where a 90° (perpendicular) angle gives sin(90°) = 1, the maximum multiplier. This is why pushing straight down on the end of a wrench handle is more effective than pushing at an angle.

Common mistakes

Mixing up lb-ft and lb-in without converting - divide by 12 to go from lb-in to lb-ft, or the result will be off by that factor.
Assuming force applied at any angle produces the same torque as perpendicular force - this calculator's simple formula only applies at exactly 90 degrees.

Frequently asked questions

What's the difference between torque and work/energy?

Both are measured in the same units (lb-ft), which causes confusion, but they're conceptually different: torque is a rotational force that may or may not cause movement, while work/energy specifically involves force acting through an actual distance moved.

How does a longer wrench or breaker bar make bolts easier to turn?

Since torque equals force times lever arm length, a longer handle lets you achieve the same torque with less force - this is the entire mechanical principle behind breaker bars and cheater pipes.

How is torque related to horsepower?

Horsepower combines torque with rotational speed (RPM) - see our Horsepower Calculator to convert between the two using HP = (Torque x RPM) / 5252.

Related calculators

See the full list of Engineering calculators, or try: