Planck mass
UniversalMeasured
= 2.176 434(24) × 10−8 kg
- Value
- 2.176 434 × 10−8 kg
- Standard uncertainty
- 2.4 × 10−13 kg
- Relative uncertainty
- 1.1 × 10−5 (11 parts per million)
- Status
- Measured
- Symbol
- Source
- CODATA 2022 via NIST · NIST entry
Use in a calculation
# Planck mass, CODATA 2022 (NIST)
planck_mass = 2.176434e-8 # kg, standard uncertainty 2.4e-13
# SciPy: scipy.constants.physical_constants['Planck mass']What it is
The unit of mass built from G, ħ and c, about 22 micrograms, large by particle standards and tiny by everyday ones.
Equations
- definition
In other units
| Unit | Value | |
|---|---|---|
| CGS (g) | 2.176 434 × 10−5 | |
| mg milligram | 0.021 764 34 | |
| µg microgram | 21.764 34 |
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 | 2.176 434(24) × 10−8 | 1.1 × 10−5 | +0.0 σ of 2018 |
| 2018 | 2.176 434(24) × 10−8 | 1.1 × 10−5 | −0.7 σ of 2014 |
| 2014 | 2.176 470(51) × 10−8 | 2.3 × 10−5 | −0.3 σ of 2010 |
| 2010 | 2.176 51(13) × 10−8 | 6.0 × 10−5 | +0.6 σ of 2006 |
| 2006 | 2.176 44(11) × 10−8 | 5.1 × 10−5 | −0.1 σ of 2002 |
| 2002 | 2.176 45(16) × 10−8 | 7.4 × 10−5 | −0.2 σ of 1998 |
| 1998 | 2.1767(16) × 10−8 | 7.4 × 10−4 |
“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).