- Symbol
- α⁻¹
- Value
- 137.035 999 177
- Unit
- (dimensionless)
- Uncertainty
- 0.000 000 021
- Copy-ready
137.035999177
The famous "roughly 1/137" — the dimensionless number that sets how strongly light couples to electric charge.
NIST, Fundamental Physical Constants — Complete Listing (2022 CODATA adjustment), retrieved 2026-07-26.
Atomic and electromagnetic constants
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UsePhysics. "Inverse fine-structure constant — 137.035 999 177 (dimensionless)." UsePhysics.com. https://usephysics.com/reference/inverse-fine-structure-constant. Value from the 2022 CODATA adjustment (NIST). Accessed [date].