How to use the e = mc² mass-energy calculator
Convert mass to energy using Einstein's equation. Enter mass in the field above; the energy, energy, tnt equivalent are computed instantly and plotted on the chart so you can see how the answer changes.
Formula
Variables
- m — Mass (g)
Worked example
With mass = 1 g, the calculator gives energy ≈ 8.9876 × 10¹³ J; energy ≈ 24,965,420 kWh; tnt equivalent ≈ 21.48076 kilotons.
Frequently asked questions
What is the formula for the e = mc² mass-energy calculation?
Energy (J) = m / 1000 × CLIGHT^2. Energy (kWh) = [Energy] / 3.6e6. TNT equivalent (kilotons) = [Energy] / 4.184e12. Here m is mass (g).
What inputs do I need for the e = mc² mass-energy calculator?
You need mass in g. 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.