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Mass-Energy Equivalence Calculator

E = mc² for any mass.

Compute the rest energy equivalent of a mass using Einstein's mass-energy equivalence E = mc².

Daniel Oh By Daniel Oh
Reviewed by Dr. Helena Ortiz
Published Last reviewed 1 min read

Inputs

kg

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

E = m · c², with c = 299,792,458 m/s.

In depth

Compute the rest energy equivalent of a mass using Einstein's mass-energy equivalence E = mc².