Momentum Calculator
PhysicsCalculate linear momentum using p = m × v. Enter mass and velocity to get the resulting momentum in kg·m/s instantly, with a clear step-by-step breakdown shown.
Reviewed by the thecalcu.com team · Last updated July 11, 2026
Momentum
What is a Momentum?
The Momentum Calculator computes linear momentum using the formula p = m × v, mass multiplied by velocity. Enter a mass in kilograms and a signed velocity in meters per second, and the calculator instantly returns the resulting momentum in kilogram-meters per second (kg·m/s).
Momentum is one of the most important conserved quantities in physics, the total momentum of a closed system stays constant unless an external force acts on it, a principle that underlies the analysis of collisions, explosions, and any interaction between moving objects. Because momentum is a vector, this calculator correctly propagates the sign of velocity through to the result, so directional scenarios are handled automatically.
If you only have displacement and time rather than velocity directly, use the Velocity Calculator first to derive a signed velocity, then bring that result here.
Why Use a Momentum Calculator?
p = m × v is a simple multiplication, but momentum calculations are frequently just one step in a larger analysis, comparing before-and-after states in a collision, or feeding into an impulse calculation, where having an instant, reliable result speeds up the overall workflow.
This calculator computes the result instantly and shows the step-by-step substitution, correctly preserving the sign of velocity so directional momentum problems (like objects moving in opposite directions before a collision) are handled without extra manual sign-tracking.
Because the result updates live, you can quickly compare the momentum of multiple objects with different masses and velocities side by side.
Who Should Use This Calculator?
Physics students verifying homework problems involving linear momentum, especially in collision and conservation-of-momentum scenarios.
Automotive safety engineers estimating the momentum involved in vehicle collisions as part of crash safety and crumple-zone design analysis.
Sports scientists and equipment designers analyzing the momentum transfer between equipment (bats, rackets, clubs) and balls or other objects.
Teachers demonstrating the momentum formula and its role in conservation principles with instant, verifiable results.
Aerospace and propulsion engineers performing quick momentum calculations as part of larger thrust or trajectory analysis.
What Insights Does This Calculator Give You?
Momentum, the single result of p = m × v, expressed in kg·m/s. This is the quantity that remains conserved (in total, across all objects) in any closed system with no external forces.
Sign propagation, because momentum directly inherits the sign of velocity, a negative velocity input produces a negative momentum, correctly representing motion in the opposite (negative) direction.
A building block for further calculations, the resulting momentum value pairs directly with the Impulse Calculator to analyze how much a given force, applied over time, would need to change an object's momentum.
How to use this Momentum calculator
Enter the mass, the mass of the object in kilograms.
Enter the velocity, the signed velocity of the object in meters per second. Use the Velocity Calculator first if you only have displacement and time.
Read the momentum result, the highlighted result shows momentum in kg·m/s, correctly signed based on the direction of the velocity entered.
Adjust and compare, change either mass or velocity to instantly see how momentum scales, useful for comparing multiple objects (like before-and-after a collision).
Check the step-by-step breakdown, expand the calculation steps to see the exact formula substitution behind your result.
Show formula & methodology ↓Show less ↑
Formula & Methodology
Momentum formula: p = m × v Variable definitions: - m, mass (kilograms) - v, velocity (meters per second, signed) - p, resulting momentum (kg·m/s) Worked example: A 1,500 kg car moving at 20 m/s. Step 1, Apply the formula: p = 1,500 kg × 20 m/s = 30,000 kg·m/s This momentum value could be compared against another vehicle's momentum in a collision scenario, where the combined momentum before impact must equal the combined momentum after impact (conservation of momentum), regardless of how the collision itself unfolds. Note: This calculator computes linear momentum for straight-line motion only. For rotating objects, a related but distinct quantity, angular momentum, uses moment of inertia and angular velocity instead of mass and linear velocity.
Frequently Asked Questions