Friction Force Calculator
Friction Force Calculator works out Friction force and Coefficient of friction from Coefficient of friction, Normal force and Friction force. The default figures on this page give friction force of 50 N; change any entry and the result, the working and the sources update together.
Your figures
Updates as you typeHow this is worked out
2 steps
- F = mu N = 0.5 x 100 = 50 N
- Acting alone on 10.197162129779283 kg that is a deceleration of 4.903325 m/s^2.
Its 4 worked examples are re-run on every release, last on 15 September 2026. What changed
Sources and references
3 sources
What the Friction Force Calculator calculates
Computes the friction force from the coefficient of friction and the normal force, and solves for either when the other two are known.
How to use this Friction Force Calculator
Enter Coefficient of friction, Normal force, Friction force and Mass on a level surface. Friction force updates as you type, and “Use a worked example” loads checked figures you can adjust. 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 Friction force, Coefficient of friction and Normal force.
The method follows Newtonian mechanics: v = dx/dt, F = ma, J = F dt = dp, and the work-energy relations, BIPM, The International System of Units (SI Brochure) and Coulomb friction model: F = mu N.
Research R3488-GT-1: mu 0.5 on a 100 N normal force example
With Coefficient of friction: 0.5, Normal force: 100, the calculator returns Friction force: 50. This example is checked against an independent source in the test suite.
What you can compare
Change one input at a time to see how it affects Friction force, Coefficient of friction and Normal force. The inputs you can vary are Coefficient of friction, Normal force, Friction force, Mass on a level surface and Gravity.
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
Is there any formula for friction?
Computes the friction force from the coefficient of friction and the normal force, and solves for either when the other two are known. On the figures this page opens with — coefficient of friction 0.5 and normal force 100 N — the friction force is 50 N. Put your own figures in their place and the working updates beside the result.
How to find frictional force without coefficient?
Computes the friction force from the coefficient of friction and the normal force, and solves for either when the other two are known. Open “How this is worked out” beside the result to see each step for your own figures.
What is the equation for friction and normal force?
On the figures this page opens with — coefficient of friction 0.5 and normal force 100 N — the friction force is 50 N. No single number fits everyone: change any figure above and the answer updates as you type, with each step of the arithmetic beside it.
What is friction force?
Computes the friction force from the coefficient of friction and the normal force, and solves for either when the other two are known. On this page it is computed from Coefficient of friction, Normal force and Friction force and shown as Friction force, Coefficient of friction and Normal force.
What information do I need for the Friction Force Calculator?
You need Coefficient of friction, Normal force, Friction force, Mass on a level surface and Gravity. The page opens with default figures that give friction force of 50 N, so you can see the scale before entering your own.
What does this Friction Force Calculator show?
It shows Friction force, Coefficient of friction, Normal force and Deceleration from friction alone, with the working and any warnings for your entries.