Planck Time

The time light takes to cross a Planck length, the smallest meaningful tick of the universe.

Specifications & Metrics

symbol

tP

status

Measured — CODATA 2022 adjustment

value

5.391247 × 10⁻⁴⁴ ± 6 × 10⁻⁴⁹ s

Relative Scale in Constants

Core Principles & Analysis

• About 5.4 × 10⁻⁴⁴ s; the age of the universe is 8 × 10⁶⁰ Planck times.
• Below this interval, the very notion of "between" has no agreed physical meaning.
• Sets the earliest moment to which classical cosmology can extrapolate.