Primary formula
J = F x Delta t; J = Delta p = m(v - u); F_avg = Delta p / Delta t.
Physics calculator
Impulse Calculator
Calculate impulse from average force and contact time, or from the change in momentum of a mass.
Last reviewed: July 21, 2026Physics mechanics engine v1.0.0
Physics calculator
Impulse Calculator
Enter values, select units and calculate locally. Results use SI internally and show rounded display values.
Decimal.js physics math
Mode
Find impulse from average force and time.
Result and visual stay hidden until you choose Calculate.
Formula and assumptions
Input assumptions
Time is greater than zero when used. Forces are average values. Mass is treated as a point mass.
Precision note
Physics Phase 1 converts compatible inputs into SI units before calculating. Decimal.js is used for arithmetic where practical; trigonometric angle factors are rounded for display.
Physics calculation flow
Parse
Read labelled inputs, selected units and calculation mode from the calculator card.
Convert
Convert compatible values to SI base or derived units without calling external services.
Calculate
Apply the selected deterministic mechanics formula and validate against NaN, Infinity and invalid divisors.
Label
Display the result, supporting unit rows, formula steps, warnings and dynamic visual below the input card.
What Impulse Calculator does
Use this page when a force acts over time or when momentum changes between two velocities.
The calculator is deterministic and runs from manual inputs only. It is a physics formula tool, so it should not be confused with a unit converter that only changes labels after a value is already known.
Formula and variables
J = F x Delta t; J = Delta p = m(v - u); F_avg = Delta p / Delta t.
The calculator converts supported units into SI base or derived units for the actual calculation, then formats the result in the selected display unit.
- J is impulse
- F is average force
- Delta t is time interval
- Delta p is momentum change
Worked examples
Use the examples below to check expected order of operations and unit handling before applying the tool to your own values.
- 10 N x 2 s = 20 N*s
- 2 kg x (8 - 3) m/s = 10 kg*m/s
- 50 N*s / 0.5 s = 100 N
Unit conversions
Length, time, mass, speed, force, energy and power units reuse the central NexaCalc conversion registry. Acceleration and spring-constant units use the same SI-first convention for mechanics formulas.
The displayed conversion rows are supporting context. They do not change the physical assumptions of the selected formula.
Common mistakes
Most errors come from mixing physical quantities that sound similar in everyday language or choosing a unit that belongs to a different dimension.
- Treating impulse as the same thing as force.
- Forgetting the velocity change sign.
- Using impact duration as zero.
Assumptions and limitations
This page is intended for educational and planning calculations, not professional engineering certification.
This calculator uses idealized physics formulas and the input values you provide. Real systems may require additional effects such as friction, drag, rotation, deformation, losses or measurement uncertainty.
- Time is greater than zero when used.
- Forces are average values.
- Mass is treated as a point mass.
- The calculator does not simulate a collision force curve.
- Material deformation, rotation and energy losses are outside this model.
Frequently asked questions
How is impulse calculated?
Impulse Calculator uses J = F x Delta t; J = Delta p = m(v - u); F_avg = Delta p / Delta t. The result is calculated from the values and units entered in the form.
Why is impulse equal to change in momentum?
Use this page when a force acts over time or when momentum changes between two velocities. Time is greater than zero when used.
What is the unit N*s?
Impulse Calculator converts compatible inputs to SI internally, then displays the selected output unit. J is impulse; F is average force; Delta t is time interval; Delta p is momentum change.
Can impulse be negative?
Impulse Calculator allows signed results only where the physics quantity can carry direction or reference-sign meaning. Divisors such as time, mass and gravity are validated before calculation.
How do I calculate average force from impact time?
Impulse Calculator uses J = F x Delta t; J = Delta p = m(v - u); F_avg = Delta p / Delta t. The result is calculated from the values and units entered in the form.
Why does longer contact time reduce average force for the same momentum change?
Impulse Calculator is formula-based. Use the related calculator when the question changes physical quantity, and use Conversion tools only when the value is already known.
Does this calculator model collisions?
Impulse Calculator uses an idealized classroom mechanics model. The calculator does not simulate a collision force curve.
What assumptions are used for average force?
Impulse Calculator uses an idealized classroom mechanics model. The calculator does not simulate a collision force curve.
How is impulse different from momentum?
Use this page when a force acts over time or when momentum changes between two velocities. Time is greater than zero when used.
When should I use Momentum Calculator?
Use this page when a force acts over time or when momentum changes between two velocities. Time is greater than zero when used.
References
- NIST Special Publication 811, Guide for the Use of the International System of Units. Relevance: SI unit symbols and derived-unit naming. Last verified: July 21, 2026. Source.
- BIPM, The International System of Units SI Brochure. Relevance: SI base and derived units used in mechanics. Last verified: July 21, 2026. Source.
- OpenStax University Physics Volume 1. Relevance: introductory mechanics formulas for motion, force, work, energy and momentum. Last verified: July 21, 2026. Source.
Physics Phase 1 references verified for SI units and mechanics formulas on July 21, 2026.
Educational disclaimer
This calculator provides mathematical results from the values, conventions and methods you enter. Verify important academic, engineering or professional work independently.