Impulse calculator
Impulse equals the change in momentum. Choose the method that fits your data.
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Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Enter method, force, contact time, mass, initial velocity and final velocity.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
J = F × Δt, or J = m × (v₂ − v₁). Speed change Δv = J ÷ m, and average force F = J ÷ Δt.
Example
Inputs: Method = From force and time, Force = 100 N, Contact time = 0.5 s, Mass = 10 kg, Initial velocity = 0 m/s. Result: Impulse: 50 N·s; Change in velocity: 5 m/s.
Limits and caveats
- The force here is an average; real impact forces peak much higher for a short moment.
- Works along one direction; a negative sign means the opposite direction.
Questions about this tool
How is impulse related to momentum?
Impulse is exactly the change in momentum, which is why N·s and kg·m/s are the same unit.
Why do airbags reduce injuries?
They stretch out the stopping time. The impulse needed to stop the passenger stays the same, so the average force drops.
Why enter a negative velocity?
When a ball bounces back its direction flips, so write the speed before the hit as negative and after as positive to capture the full change.