Constants & Units · constant

Reduced Planck constant

ℏ = 1.054 571 817… × 10⁻³⁴ J s

Unit: J s
Value: 1.054 571 817… × 10⁻³⁴
Exact: yes
Note: Planck's constant per radian. The natural unit of angular momentum and the ℏ in every quantum equation.
Symbol: ℏ
Category: Universal
Numeric: 1.054571817e-34
Uncertainty: exact (h/2π)

Equations

Heisenberg Uncertainty Principle Schrödinger Equation Fine-Structure Constant Klein–Gordon Equation Feynman Path Integral Dirac Equation Chandrasekhar Limit

Referenced by

equation

Chandrasekhar Limit Dirac Equation Feynman Path Integral Fine-Structure Constant Heisenberg Uncertainty Principle Klein–Gordon Equation Schrödinger Equation

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From the Constants database in Notion, last edited 2026-08-15. This page is the row, rendered by the build; nothing on it is written by hand.