Kinetic Energy Formula and Calculator: KE = 1/2 mv²
The kinetic energy formula is KE = ½mv² for classical translational motion. Enter two known quantities to calculate energy, mass or speed. The calculator converts its supported units to kilograms, metres per second and joules.
- Free to use
- No sign-up
- Runs in your browser
Kinetic energy calculator
Energy & Motion Practice Pack
Printable physics practice: kinetic and potential energy formula sheet, two worksheets with worked answers, a unit conversion table and a lab data sheet for measuring speed and energy.
- Formula sheet (PDF)
- KE worksheet (PDF, DOCX)
- PE ↔ KE worksheet (PDF, DOCX)
- Lab data (XLSX)
Formats: PDF, DOCX, XLSX. Instant download after payment (link valid 72 hours, up to 5 downloads). AI-assisted: the templates were drafted with AI help and reviewed and laid out before publishing.
$5.00 USD, one-time 4 files · about $1.25 each
- Instant download
- 7-day refund
- Secure checkout by Stripe
✓ Classroom use included
7-day money-back guarantee. Full refund within 7 days of purchase, even after you download.
Free sample: Energy Conversion Worksheet (PDF, 95 KB)
Full refund within 7 days — see the refund policy and license.
License: personal and classroom use. Teachers may print and photocopy these files for the students in their own classes, and share them in a password-protected class space (e.g. Google Classroom). Please do not resell, redistribute, or post the files on public websites. One purchase covers one teacher.
Free printables
Single sheets you can print right now, no sign-up. The full pack adds every sheet in one download plus the editable files.
Kinetic Energy Lab Data SheetKinetic energy formula examples
| Mass (kg) | Speed (m/s) | Energy (J) |
|---|---|---|
| 2 | 3 | 9 |
| 2 | 6 | 36 |
| 10 | 5 | 125 |
| 1 | 0 | 0 |
Doubling speed from 3 to 6 m/s at the same 2 kg mass raises energy from 9 to 36 J. The squared speed term makes this four times the energy.
Choose the unknown quantity
- Energy: KE = ½mv²; use positive mass and nonnegative speed.
- Mass: m = 2KE ÷ v²; speed must be greater than zero.
- Speed: v = √(2KE ÷ m); use positive mass and nonnegative energy.
Invalid required inputs clear the previous result and display a message. A negative mass is rejected. The extra momentum and equivalent-height figures are derived from the same inputs; they are not additional solve modes.
Supported units and limits
Mass inputs: kg, g, lb and metric tonnes. Speed inputs: m/s, km/h, mph and ft/s. Energy inputs: J, kJ, MJ, cal, ft·lbf and kWh. This model does not calculate rotational or relativistic kinetic energy.
Frequently asked questions
Why is speed squared?
In this classical model, energy is proportional to the square of speed. Twice the speed gives four times the energy at fixed mass.
Can I enter zero?
Zero speed is allowed when solving energy; zero energy is allowed for mass or speed. Mass must be positive and mass-solving speed must be positive.
Is this a rotational-energy calculator?
No. It uses classical translational kinetic energy and does not take a moment of inertia.