Atomic unit of momentum = 1.992 851 915 45 × 10−24 kg·m·s⁻¹

Value
1.992 851 915 45 × 10−24
Unit
kg·m·s⁻¹
Uncertainty
0.000 000 000 31 × 10⁻²⁴
Copy-ready
1.99285191545e-24

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

Quantum-chemistry and atomic-physics codes report momentum 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

Link to or cite this value

Link from a web page

Plain HTML for any page that accepts markup.

<a href="https://usephysics.com/reference/atomic-unit-of-momentum">Atomic unit of momentum — 1.992 851 915 45 × 10−24 kg·m·s⁻¹ — UsePhysics</a>

Link from Markdown

For READMEs, wikis and notes.

[Atomic unit of momentum — 1.992 851 915 45 × 10−24 kg·m·s⁻¹ — UsePhysics](https://usephysics.com/reference/atomic-unit-of-momentum)

Cite it in a document

Replace [date] with the day you consulted the page. The line credits NIST/CODATA for the values.

UsePhysics. "Atomic unit of momentum — 1.992 851 915 45 × 10−24 kg·m·s⁻¹." UsePhysics.com. https://usephysics.com/reference/atomic-unit-of-momentum. Value from the 2022 CODATA adjustment (NIST). Accessed [date].

All physical constants

Constants and formula sheetAtomic unitsAll calculators