Impulse Calculator

Calculate impulse from force and time, and the velocity change it produces.

About Impulse Calculator

The same impulse can be delivered by a large force briefly or a small force for longer. Since injury depends on force rather than impulse, extending the time is the whole design goal of protective equipment. Doubling the stopping time halves the force for an identical change in momentum, which is why padding and progressive crush structures work.

Formula

Impulse

J = F Δt = Δp = m Δv

J: Impulse in newton seconds
Δv: Resulting change in velocity

Worked example

With the default values below, Impulse Calculator returns Impulse of 400.000. Change any input above and every figure here is recalculated in your browser.

Inputs used

Average forceminimum 0 N: 5,000 N
Duration of the forceminimum 0.001 s: 0.08 s
Massminimum 0.01 kg: 75 kg

Results

Impulse: 400.000 N s
Change in Velocity: 5.333 m/s
Change in Momentum: 400.000 kg m/s
Force Needed if the Duration Doubled: 2,500.00 N
Acceleration Experienced: 6.80 g

Step by step

1Values used
2Impulse
3Impulse= 400.000 N s
4Change in Velocity= 5.333 m/s
5Change in Momentum= 400.000 kg m/s
6Force Needed if the Duration Doubled= 2,500.00 N
7Acceleration Experienced= 6.80 g

Assumptions and limits

The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is Impulse calculated?

J = F Δt = Δp = m Δv The same impulse can be delivered by a large force briefly or a small force for longer. Since injury depends on force rather than impulse, extending the time is the whole design goal of protective equipment.

Why does Impulse matter?

Doubling the stopping time halves the force for an identical change in momentum, which is why padding and progressive crush structures work.

What values do I need to enter?

This calculator takes 3 inputs: Average force, Duration of the force, Mass. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.