How to use the relativistic kinetic energy calculator
Compute relativistic kinetic energy and momentum. Enter rest mass, speed as fraction of c in the fields above; the lorentz factor γ, kinetic energy, kinetic energy, momentum are computed instantly and plotted on the chart so you can see how the answer changes.
Formula
Variables
- m — Rest mass (kg)
- v — Speed as fraction of c
Worked example
With rest mass = 9.109e-31 kg, speed as fraction of c = 0.9, the calculator gives lorentz factor γ ≈ 2.294157; kinetic energy ≈ 1.0595 × 10⁻¹³ J; kinetic energy ≈ 0.6612852 MeV; momentum ≈ 5.6384 × 10⁻²² kg·m/s.
Frequently asked questions
What is the formula for the relativistic kinetic energy calculation?
Lorentz factor γ = 1 / √(1-v × v). Kinetic energy (J) = ([Lorentz factor γ]-1) × m × CLIGHT^2. Kinetic energy (MeV) = [Kinetic energy] / QE / 1e6. Momentum (kg·m/s) = [Lorentz factor γ] × m × v × CLIGHT. Here m is rest mass (kg), v is speed as fraction of c.
What inputs do I need for the relativistic kinetic energy calculator?
You need rest mass in kg, speed as fraction of c. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use this calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.