Torque Calculator
Torque calculator works out Torque and Power from Force (or brake clamp force), Force unit and Lever arm / effective radius. The default figures on this page give torque of 50.0000 Nm; change any entry and the result, the working and the sources update together.
Your figures
Updates as you typeHow this is worked out
3 steps
- tau = F r sin(theta) = 100 N x 0.5 m x sin(90 deg) = 50 N m
- omega = 2 pi x 3000 / 60 = 314.15927 rad/s.
- P = tau omega = 50 x 314.15927 = 15707.96 W = 15.708 kW = 21.0647 hp.
Its 5 worked examples are re-run on every release, last on 15 September 2026. What changed
Sources and references
3 sources
What the torque calculator calculates
Converts between torque, rotational speed and power in both SI and imperial units, computes torque from a force on a lever arm, and computes brake torque from clamp force, pad friction and effective rotor radius.
How to use this torque calculator
Enter Force (or brake clamp force), Force unit, Lever arm / effective radius and Length unit. Torque updates as you type. Change one figure at a time to see what drives the result.
How the result is worked out
Open “How this is worked out” beside the result for the step-by-step calculation behind Torque, Power and Angular velocity.
The method follows Definition of the moment of a force and of rotational power, NIST Special Publication 811, Guide for the Use of the International System of Units and SAE J866 / brake system fundamentals: braking torque = 2 mu N r_effective for a two-pad caliper.
What you can compare
Change one input at a time to see how it affects Torque, Power and Angular velocity. The inputs you can vary are Force (or brake clamp force), Force unit, Lever arm / effective radius, Length unit, Angle between the force and the lever arm and Torque.
Results are general information, not financial, tax, legal, medical or engineering advice. Check any decision that matters with a qualified professional.
See something wrong? Report a problem with this calculator
Frequently asked questions
How do I calculate torque?
Converts between torque, rotational speed and power in both SI and imperial units, computes torque from a force on a lever arm, and computes brake torque from clamp force, pad friction and effective rotor radius. Open “How this is worked out” beside the result to see each step for your own figures.
How do I convert torque in lbs to Nm?
It needs Force (or brake clamp force), Force unit, Lever arm / effective radius, Length unit, Angle between the force and the lever arm and Torque. Nothing else is required, and the figures stay in your browser.
How to calculate ft/lbs of torque?
The result gives Torque, Power, Angular velocity and Rotational speed, each labelled with its unit so the figure can be read on its own.
How to calculate torque for bolts?
The page opens with worked default figures: torque of 50.0000 Nm. Replace them with your own and every figure updates as you type.
What information do I need for the torque calculator?
You need Force (or brake clamp force), Force unit, Lever arm / effective radius, Length unit, Angle between the force and the lever arm, Torque, Torque unit and Rotational speed. The page opens with default figures that give torque of 50.0000 Nm, so you can see the scale before entering your own.
What does this torque calculator show?
It shows Torque, Power, Angular velocity and Rotational speed, with the working and any warnings for your entries.