Planck Mass

The mass whose Compton wavelength and Schwarzschild radius coincide — the quantum-gravity scale.

Specifications & Metrics

symbol

mP

status

Measured — CODATA 2022 adjustment

value

2.176434 × 10⁻⁸ ± 2.4 × 10⁻¹³ kg

Relative Scale in Constants

Core Principles & Analysis

• About 22 micrograms, the mass of a flea egg and utterly enormous for a fundamental unit.
• The only Planck quantity at a humanly conceivable scale, which is why quantum gravity hides.
• Defines the energy density at which the early universe left the Planck era.