About the Torque Calculator
Torque is the turning effect of a force. A longer spanner makes the same push turn a bolt more easily because it multiplies the force by the distance from the pivot. This calculator offers two ways: a force on a lever arm, with the angle between them, or the power and rotation speed of a motor or engine. It gives the answer in newton-metres, pound-feet, kilogram-force metres and pound-inches. Type either the force and lever arm, or the power and speed and the torque appears at once, with a few related figures underneath, and you can copy the result with one tap. The sums run in your browser, so nothing you enter is uploaded.
Updated October 2026
How to use the Torque Calculator
- 1Enter either the force and lever arm, or the power and speed.
- 2Pick the units or options from the menus if the torque tool offers them.
- 3Read the torque in the large result box.
- 4Look at the extra rows for related figures.
- 5Press Copy result to keep the answer.
When you need the torque
Mechanics use torque to tighten wheel nuts and engine bolts to the figure in the manual. Engineers use the power and speed form to choose a motor or a gearbox, since a motor of a given power gives more torque at lower speed.
The sine of the angle matters because only the part of the force at a right angle to the arm turns the bolt. At 90 degrees you get the full effect. Pulling along the arm gives no torque at all.
How the torque is worked out
Torque = force × lever arm × sin(angle). From power: torque = power ÷ (2π × rpm ÷ 60). A 200 N push at the end of a 0.5 m spanner, at a right angle, gives 100 N·m, or 73.8 lbf·ft. A 1 kW motor at 3,000 rpm gives 3.18 N·m. A 100 kW engine at 6,000 rpm gives 159.2 N·m.
Every answer on this page comes from that one rule, so you can check any result by hand with a calculator. The figures shown underneath, such as other units, are conversions of the same answer.
- Two methods
- Four torque units
- Angle of the force
Mistakes to avoid with torque
Do not mix up torque and power: power is torque times speed. A tool with high torque at low speed can have the same power as one with low torque at high speed. Check the units of the figures in a manual, which are often pound-feet or pound-inches.
On phone and computer
On a phone, type into the boxes one after another and read the torque underneath; Copy result puts it on the clipboard for a message or a note. On a computer the inputs sit on the left and the answer on the right, so you can change one figure and watch the torque move. The torque calculator works the same on both. Torque and power are closely linked. Convert units with the Torque Converter, work out speed ratios with the Gear Ratio Calculator, and see engine power with the Horsepower Calculator.
Features
- Right-angle force gives the most
- Power = torque × speed
- Check the unit in a manual
- Clear messages when the torque inputs make no sense
- Copy the result with one tap
- Private: nothing is uploaded
Frequently asked questions
How do I calculate torque?
Torque = force × lever arm × sin(angle). From power: torque = power ÷ (2π × rpm ÷ 60). A 200 N push at the end of a 0.5 m spanner, at a right angle, gives 100 N·m, or 73.8 lbf·ft. A 1 kW motor at 3,000 rpm gives 3.18 N·m. A 100 kW engine at 6,000 rpm gives 159.2 N·m.
What is the formula for torque?
Torque = force × lever arm × sin(angle). From power: torque = power ÷ (2π × rpm ÷ 60). The torque calculator applies it exactly and rounds only the displayed answer to six significant figures.
What is the difference between N·m and joules?
Both are force times distance, but torque is a turning effect and energy is work done. The units look the same, but the quantities are different.
How do I get lb-ft from N·m?
Multiply by 0.737562.
Why does torque fall as an engine speeds up for a fixed power?
Power is fixed at torque times speed, so more speed means less torque.
Is this torque calculator free and private?
Yes. It is free, needs no account and runs in your browser, so the numbers you type are not uploaded or stored.