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Physics Tools · Updated October 21, 2026 · Reviewed by FormatFlow Editorial

Momentum & Impulse Calculator

You can calculate momentum from mass and velocity, or impulse from force and time, and solve for any missing quantity in either relation with unit choices and signed directions.

Runs in your browserFree · No sign-up · No watermark
m, v → p; F, Δt → JRuns in your browser
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Everything runs locally in this tab. No file is uploaded while the tool loads.

This tool runs in your tab. Nothing is uploaded and no copy is stored.

How files are handled

At a glance

Works with
m, v → p; F, Δt → J
Processing
In your browser
Price
Free, no account
Updated
October 21, 2026
All Physics Tools

About Momentum & Impulse Calculator

Momentum is mass multiplied by velocity, and impulse is the change in momentum produced by a force acting over time. The two ideas connect: a long, gentle push and a short, hard one can produce the same momentum change, which is why safety equipment is designed to extend collision time.

This calculator has separate momentum and impulse tabs. The momentum tab solves p, m or v with kilograms, grams, m/s and km/h available; the impulse tab solves impulse, average force, time or velocity change, with newtons, kilonewtons, seconds and milliseconds.

What this tool does

The details that matter when you use Momentum & Impulse Calculator for real work.

  • Momentum and impulse tabs

    Two focused panels keep the mass-velocity relation separate from the force-time relation.

  • Solve every quantity

    Find momentum, mass or velocity, or impulse, average force, time interval or velocity change.

  • Flexible units

    Mass in kg or g, velocity in m/s or km/h, momentum in kg·m/s, N·s or g·m/s, force in N or kN, time in s or ms.

  • Signed directions

    Negative velocity and force values are accepted and interpreted as the opposite direction along the chosen axis.

  • Substituted working

    Each result prints the relation with the converted values inserted, so the arithmetic can be checked.

  • Impulse-momentum link

    The impulse tab reports Δp and, when a mass is entered, the resulting velocity change Δv = J ÷ m.

How to use Momentum & Impulse Calculator

No account, no installation — the whole job happens in this browser tab.
  1. 01

    Choose momentum or impulse

    Use the top toggle for the relation you need: p = m·v or J = F·Δt = Δp.

  2. 02

    Pick the quantity to solve

    Select the missing value on the second toggle, and the calculator hides the value it will compute.

  3. 03

    Enter the known values with units

    Choose units for mass, velocity, momentum, force or time; all values are normalized before calculation.

  4. 04

    Read the result and direction

    The headline gives the solved value, and the summary shows the related quantities and their units.

  5. 05

    Check the working

    The formula panel shows the converted values in the equation; Reset clears the entries for the next problem.

How this tool works

Works with
m, v → p; F, Δt → J
Processing
Client-side, in your browser. Nothing is uploaded.
Requirements
Chrome, Edge, Firefox or Safari · JavaScript enabled

Limitations worth knowing

  • Uses an average force over the interval; a real force that varies with time needs integration or measurement.
  • Applies classical mechanics at ordinary speeds; relativistic and quantum momentum are outside the model.
  • Assumes constant mass, so variable-mass systems such as rockets need the rocket equation instead.

Privacy and file handling

Mass, velocity, force and time values are processed entirely in your browser. Nothing is uploaded, stored or logged, and no network request is made.

Read the full privacy policy

Momentum & Impulse Calculator FAQ

Short, direct answers to the questions people ask before using this tool.
What is momentum in physics?
Momentum is the product of an object's mass and its velocity, p = m·v, measured in kilogram meters per second (kg·m/s). It measures how hard it is to stop a moving object, and it is a vector, so its direction matters as much as its magnitude.
What is impulse and how is it related to momentum?
Impulse is the average force multiplied by the time it acts, J = F·Δt, and it equals the change in momentum Δp. That is the impulse-momentum theorem: a given momentum change can come from a large force over a short time or a small force over a long time.
Why is momentum a signed quantity in this calculator?
Momentum and velocity are vectors. The calculator works on one chosen axis, so a positive value means motion in the positive direction and a negative value means the opposite direction. Subtracting the two directions is how a reversal of motion appears.
Can I enter a negative velocity or force?
Yes. A negative velocity means motion opposite to the positive axis, and a negative force means a push in that opposite direction. The magnitude is the size of the quantity; the sign carries the direction information, which matters for changes in momentum.
Why must mass and time be positive in the calculator?
Mass and the length of a time interval are magnitudes, so a negative value has no physical meaning. A time of zero would make an impulse or a force calculation undefined, so the tool requires a positive interval and reports an error instead.
How do airbags reduce the force in a collision?
An airbag increases the time over which a passenger's momentum change happens. Because impulse J = F·Δt equals the fixed momentum change Δp, a longer Δt means a smaller average force, which is why the airbag and crumple zone reduce injury risk.
How do I convert kilometers per hour to meters per second?
Divide by 3.6: 72 km/h is 20 m/s. The calculator offers both units on the velocity selector and converts to m/s before applying p = m·v, so the result is consistent with the other SI units in the calculation.
Is the momentum calculator valid at very high speeds?
It uses classical p = m·v, which is accurate for everyday speeds. As speeds approach a significant fraction of the speed of light, relativistic momentum needs a different expression, and at the atomic scale quantum mechanics replaces classical momentum entirely.

Background reading

Format guides that explain the trade-offs behind Momentum & Impulse Calculator.