Kinetic Energy Calculator
Calculate kinetic energy with KE = 1/2 mv^2. Enter mass and speed in practical units, then review joules, kilojoules, calories, kWh, SI-normalized mass, SI-normalized speed, and momentum.
Formula
KE = 1/2 mv^2
Mass units
kg, g, lb
Speed units
m/s, km/h, mph, ft/s
Live calculator
Mass and speed
Kinetic energy
100 J
Mass
2 kg
Speed
10 m/s
Momentum
20 kg m/s
| Energy in J | 100 J |
|---|---|
| Energy in kJ | 0.1 kJ |
| Energy in cal | 23.900574 cal |
| Energy in kWh | 2.778e-5 kWh |
Convert motion inputs into kinetic energy
Joule result
Calculate kinetic energy in SI units from normalized mass and speed.
Energy conversions
Review joules, kilojoules, calories, and kilowatt-hours from the same result.
Momentum side check
See mass times velocity as a companion motion quantity.
Kinetic energy formulas used on this page
Translational kinetic energy depends linearly on mass and quadratically on speed.
Working formulas
Kinetic energy
KE = 1/2 m v^2
Mass is in kilograms and speed is in meters per second.
Momentum
p = m v
Momentum is shown as a companion value in kg m/s.
Kilojoules
kJ = J / 1000
Converted energy values are generated from the joule result.
Symbols
- KE - kinetic energy
- Energy of motion, shown first in joules.
- m - mass
- Mass normalized to kilograms before calculation.
- v - speed
- Speed normalized to meters per second before squaring.
- p - momentum
- Mass multiplied by velocity.
Kinetic energy results that make the squared speed visible
Motion unit conversions
- Mass can be entered as kilograms, grams, or pounds and is normalized to kilograms.
- Speed can be entered as m/s, km/h, mph, or ft/s and is normalized before squaring.
- Energy outputs include joules, kilojoules, calories, and kilowatt-hours.
- Momentum is shown beside energy to support related worksheet questions.
Formula context
- The formula block explains why speed has a squared effect on kinetic energy.
- FAQ answers cover negative speed, mass units, energy units, and momentum differences.
- Related links connect kinetic energy to motion and power worksheets.
- The page is scoped to educational mechanics, not vehicle safety or impact prediction.
Kinetic energy support for mechanics practice
Students
Check homework arithmetic while keeping SI conversions and formula variables visible.
Teachers
Create worksheet examples with formulas, units, and result summaries that print cleanly.
Formula reviewers
Audit values across common unit systems before comparing physics examples.
How it works in three quick steps.
Enter mass
Type the mass and choose kilograms, grams, or pounds.
Enter speed
Type speed and choose m/s, km/h, mph, or ft/s.
Read energy
Use the joule result and conversion table to compare energy units.
Save or print a kinetic energy result
Copy the result
Copy the formula result and normalized SI values into notes, worksheets, or lesson drafts.
Print the calculator
Print inputs, outputs, formula notes, FAQ answers, and related physics links.
Compare examples
Change one variable at a time to see how unit conversions affect the final value.
Why kinetic energy needs speed-unit normalization
Kinetic energy calculations are sensitive to speed because the formula squares velocity. A small unit mistake can become a large energy mistake. Toolarithm's Kinetic Energy Calculator converts mass to kilograms and speed to meters per second before applying KE = 1/2 mv^2. The output table then converts the same joule result into kilojoules, calories, and kilowatt-hours for comparison.
This page supports mechanics lessons, worksheet checks, and unit-conversion practice. It deliberately does not estimate real-world collision forces or safety risk. Those questions need stopping distance, contact time, material behavior, and engineering context beyond a single kinetic energy formula.
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