Planck time
UniversalMeasured
= 5.391 247(60) × 10−44 s
- Value
- 5.391 247 × 10−44 s
- Standard uncertainty
- 6 × 10−49 s
- Relative uncertainty
- 1.1 × 10−5 (11 parts per million)
- Status
- Measured
- Symbol
- Source
- CODATA 2022 via NIST · NIST entry
Use in a calculation
Plain
LaTeX
Python
# Planck time, CODATA 2022 (NIST)
planck_time = 5.391247e-44 # s, standard uncertainty 6e-49
# SciPy: scipy.constants.physical_constants['Planck time']What it is
The time light takes to cross one Planck length.
Equations
- definition
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 | 5.391 247(60) × 10−44 | 1.1 × 10−5 | +0.0 σ of 2018 |
| 2018 | 5.391 247(60) × 10−44 | 1.1 × 10−5 | +0.7 σ of 2014 |
| 2014 | 5.391 16(13) × 10−44 | 2.4 × 10−5 | +0.3 σ of 2010 |
| 2010 | 5.391 06(32) × 10−44 | 5.9 × 10−5 | −0.7 σ of 2006 |
| 2006 | 5.391 24(27) × 10−44 | 5.0 × 10−5 | +0.1 σ of 2002 |
| 2002 | 5.391 21(40) × 10−44 | 7.4 × 10−5 | +0.2 σ of 1998 |
| 1998 | 5.3906(40) × 10−44 | 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).