Proton mass energy equivalent
Atomic & nuclearMeasured
= 1.503 277 618 02(47) × 10−10 J
- Value
- 1.503 277 618 02 × 10−10 J
- Standard uncertainty
- 4.7 × 10−20 J
- Relative uncertainty
- 3.1 × 10−10 (313 parts per trillion)
- Status
- Measured
- Symbol
- Source
- CODATA 2022 via NIST · NIST entry
Use in a calculation
# proton mass energy equivalent, CODATA 2022 (NIST)
proton_mass_energy_equivalent = 1.50327761802e-10 # J, standard uncertainty 4.7e-20
# SciPy: scipy.constants.physical_constants['proton mass energy equivalent']What it is
The rest energy (mass × c²) of the proton, the nucleus of the hydrogen atom, in joules.
In other units
| Unit | Value | |
|---|---|---|
| CGS (cm2 g s−2) | 0.001 503 277 618 02 | |
| keV kiloelectronvolt | 938 272.089 431 | |
| MeV megaelectronvolt | 938.272 089 431 | |
| GeV gigaelectronvolt | 0.938 272 089 431 | |
| erg erg | 0.001 503 277 618 02 |
Converted with ConstantID's unit table; digits are rounded to the precision of the value, and a long exact value is rounded only for display. The relative uncertainty is unchanged by conversion to an exactly defined unit.
How the value changed, 1998–2022
Each point is one CODATA adjustment, plotted as its difference from the 2022 value; the bars show one standard uncertainty (an arrowhead means the bar runs off the chart).
Relative uncertainty
| CODATA | Value (uncertainty) | Relative uncertainty | Change from previous |
|---|---|---|---|
| 2022 | 1.503 277 618 02(47) × 10−10 | 3.1 × 10−10 | +4.4 σ of 2018 |
| 2018 | 1.503 277 615 98(46) × 10−10 | 3.1 × 10−10 | +1.3 σ of 2014 |
| 2014 | 1.503 277 593(18) × 10−10 | 1.2 × 10−8 | +1.7 σ of 2010 |
| 2010 | 1.503 277 484(66) × 10−10 | 4.4 × 10−8 | +1.7 σ of 2006 |
| 2006 | 1.503 277 359(75) × 10−10 | 5.0 × 10−8 | −0.3 σ of 2002 |
| 2002 | 1.503 277 43(26) × 10−10 | 1.7 × 10−7 | +1.0 σ of 1998 |
| 1998 | 1.503 277 31(12) × 10−10 | 8.0 × 10−8 |
“Change from previous” is the shift in the value divided by the standard uncertainty of the previous adjustment. Earlier values are converted into the current unit where NIST changed it (for example J s to J Hz⁻¹).