Elementary charge over h-bar

$e/ℏ$ = 1.519 267 447… × 10¹⁵ A J⁻¹

Value: 1.519 267 447… × 10¹⁵ A J⁻¹
Standard uncertainty: exact
Relative uncertainty: exact
Status: Exact
Symbol: $e/ℏ$
Source: CODATA 2022 via NIST · NIST entry

NIST prints this exact value cut to 10 digits. ConstantID recomputes it from the defining constants: 1.519 267 447 878 626 201 250 234 970 89 × 10¹⁵…

Use in a calculation

# elementary charge over h-bar, CODATA 2022 (NIST)
elementary_charge_over_h_bar = 1.519267447878626201250234970894513e15  # A J^-1, exact

# SciPy: scipy.constants.physical_constants['elementary charge over h-bar']

What it is

The elementary charge divided by the reduced Planck constant. It is exact since 2019 and equals π times the Josephson constant.

It is built only from constants with exact values, so it is exact too.

How the value changed, 1998–2022

CODATA	Value (uncertainty)	Relative uncertainty	Change from previous
2022	1.519 267 447… × 10¹⁵	exact	exact
2018	1.519 267 447… × 10¹⁵	exact

“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).

Related constants

Electromagnetic exact

e

Elementary charge 1.602 176 634 × 10⁻¹⁹ C