Avogadro Constant

The exact number of constituent particles in one mole of substance, defining the SI mole.

Core Principles & Analysis

• Exactly 6.02214076 × 10²³ entities per mole since the 2019 SI redefinition.
• Named for Amedeo Avogadro, whose 1811 hypothesis held that equal gas volumes contain equal molecule counts.
• Counting the atoms in near-perfect silicon-28 spheres measured it precisely enough to justify fixing it.

Specifications & Metrics

• SYMBOL: N_A
• STATUS: Exact — SI defining constant (2019)
• VALUE: 6.02214076 × 10²³ mol⁻¹

Open in the Simulator — run this concept live