Calculate mass or energy with E=mc², converting amu, grams, kilograms, or pounds to joules, kJ, cal, kcal, or eV in your chosen unit.
Customize This Calculator
Build your own version. Describe what you want changed, added, or compared.
Related Calculators
- Joules To Wavenumber Calculator
- Ev To Kj/Mol Calculator
- Volts to Joules Calculator
- KWH Calculator
- All Unit Converters
Amu To Joules Formula
The following formula is used to calculate the rest-energy equivalent in Joules from a mass given in atomic mass units (amu). Since E = mc2 requires mass in kilograms, the amu value must be converted to kg first.
Variables:
- E is the energy in Joules (J)
- mamu is the mass in atomic mass units (amu)
- 1 amu = 1.66053906660×10-27 kg
- c is the speed of light in vacuum in meters per second (m/s), which is 299,792,458 m/s (≈ 3.00 × 108 m/s)
To calculate the energy in Joules, first convert the mass from amu to kilograms using 1 amu = 1.66053906660×10-27 kg, then multiply that mass (in kg) by the square of the speed of light in vacuum. The result is the energy in Joules.
| Mass (amu) | Energy (J) | Energy (eV) |
|---|---|---|
| 0.5 | 7.46e-11 | 4.66e8 |
| 1 | 1.49e-10 | 9.31e8 |
| 2 | 2.98e-10 | 1.86e9 |
| 4 | 5.97e-10 | 3.73e9 |
| 12 | 1.79e-9 | 1.12e10 |
| 14 | 2.09e-9 | 1.30e10 |
| 16 | 2.39e-9 | 1.49e10 |
| 18 | 2.69e-9 | 1.68e10 |
| 20 | 2.98e-9 | 1.86e10 |
| 24 | 3.58e-9 | 2.24e10 |
| 28 | 4.18e-9 | 2.61e10 |
| 32 | 4.78e-9 | 2.98e10 |
| 35.5 | 5.30e-9 | 3.31e10 |
| 40 | 5.97e-9 | 3.73e10 |
| 56 | 8.36e-9 | 5.22e10 |
| 63.5 | 9.48e-9 | 5.91e10 |
| 79.9 | 1.19e-8 | 7.36e10 |
| 107.9 | 1.61e-8 | 1.01e11 |
| 197 | 2.94e-8 | 1.84e11 |
| 238 | 3.55e-8 | 2.22e11 |
| Constants: 1 amu = 1.66053906660×10-27 kg; c = 299,792,458 m/s. Per amu: 1 amu ≈ 1.492418×10-10 J ≈ 9.31494×108 eV. | ||
What is Amu To Joules?
Amu to Joules is a conversion from atomic mass units (amu) (a unit of mass) to Joules (J) (a unit of energy) using mass–energy equivalence. Specifically, it converts a mass value to its rest-energy equivalent using Einstein’s equation E = mc2 after converting amu to kilograms.
How to Calculate Amu To Joules?
The following steps outline how to calculate the energy in Joules (J) from a mass in amu.
- First, determine the mass in atomic mass units (amu).
- Convert the mass to kilograms (kg) using 1 amu = 1.66053906660×10-27 kg.
- Use the speed of light in vacuum, c = 299,792,458 m/s (≈ 3.00 × 108 m/s).
- Apply the formula E = mkg × c2 to calculate the energy in Joules (J).
- After inserting the variables and calculating the result, check your answer with a calculator.
Example Problem:
Use the following variables as an example problem to test your knowledge.
mass (m) in atomic mass units (amu) = 5
speed of light (c) in meters per second (m/s) = 299,792,458 (≈ 3.00 × 108)
Solution (rest-energy equivalent): Convert mass to kilograms: m = 5 amu × 1.66053906660×10-27 kg/amu = 8.302695333×10-27 kg. Then E = m c2 ≈ (8.302695333×10-27 kg) × (299,792,458 m/s)2 ≈ 7.46×10-10 J.
