Atomic unit of time = 2.418 884 326 5864 × 10−17 s

Value
2.418 884 326 5864 × 10−17
Unit
s
Uncertainty
0.000 000 000 0026 × 10⁻¹⁷
Copy-ready
2.4188843265864e-17

The atomic unit of time: the natural size of time in the Hartree system, where ℏ, e, mₑ and 4πε₀ all equal 1.

Quantum-chemistry and atomic-physics codes report time in atomic units; multiply a result by this value to get it in SI.

NIST, Fundamental Physical Constants — Complete Listing (2022 CODATA adjustment), retrieved 2026-07-26.

Atomic units

Atomic unit of 1st hyperpolarizabilityAtomic unit of 2nd hyperpolarizabilityAtomic unit of charge densityAtomic unit of currentAtomic unit of electric dipole momentAtomic unit of electric fieldAtomic unit of electric field gradientAtomic unit of electric polarizabilityAtomic unit of electric potentialAtomic unit of electric quadrupole momentAtomic unit of forceAtomic unit of magnetic dipole momentAtomic unit of magnetic flux densityAtomic unit of magnetizabilityAtomic unit of momentumAtomic unit of permittivityAtomic unit of timeAtomic unit of velocity

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UsePhysics. "Atomic unit of time — 2.418 884 326 5864 × 10−17 s." UsePhysics.com. https://usephysics.com/reference/atomic-unit-of-time. Value from the 2022 CODATA adjustment (NIST). Accessed [date].

All physical constants

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