- Symbol
- a₀
- Value
- 5.291 772 105 44 × 10−11
- Unit
- m
- Uncertainty
- 0.000 000 000 82 × 10⁻¹¹
- Copy-ready
5.29177210544e-11
The natural length scale of the hydrogen atom — roughly half an ångström.
NIST, Fundamental Physical Constants — Complete Listing (2022 CODATA adjustment), retrieved 2026-07-26.
Atomic and electromagnetic constants
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/bohr-radius">Bohr radius — 5.291 772 105 44 × 10−11 m — UsePhysics</a>
Link from Markdown
For READMEs, wikis and notes.
[Bohr radius — 5.291 772 105 44 × 10−11 m — UsePhysics](https://usephysics.com/reference/bohr-radius)
Cite it in a document
Replace [date] with the day you consulted the page. The line credits NIST/CODATA for the values.
UsePhysics. "Bohr radius — 5.291 772 105 44 × 10−11 m." UsePhysics.com. https://usephysics.com/reference/bohr-radius. Value from the 2022 CODATA adjustment (NIST). Accessed [date].