Length · Unit Converter

Convert Bohr Radius to Fermi

Convert bohr radii to fermis instantly. 1 bohr radius = 52917.7210903 fermi — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Fermi to Bohr Radius converter for the reverse conversion.

Written by Sunith Babu L, Ph.D., Lead Engineer Reviewed by Girish V Kulkarni Ph.D.
Length category 2 min read Published Last reviewed Updated

Units explained

Atomic / Physics

Bohr Radius

What is a bohr radius?

The Bohr radius is approximately 5.292×10⁻¹¹ meters — the most probable distance between the proton and electron in a hydrogen atom in its ground state.

Origin of the bohr radius

Defined by Niels Bohr in his 1913 model of the hydrogen atom. The current CODATA 2018 value of 5.29177210903×10⁻¹¹ m is derived from the elementary charge, electron mass, and Planck's constant.

Where it is used

The Bohr radius is used throughout atomic physics, quantum chemistry, and computational chemistry as the natural length scale for electronic-structure calculations. The atomic unit (a.u.) of length equals the Bohr radius.

When and where it was developed

Defined by Bohr in 1913; current value via CODATA 2018.

Atomic / Physics

Fermi

What is a fermi?

A fermi is a unit of length equal to one femtometer (1×10⁻¹⁵ m). It is named after physicist Enrico Fermi and is widely used in nuclear physics as a synonym for the femtometer.

Origin of the fermi

The fermi was introduced informally in mid-20th-century nuclear physics literature. Although the BIPM has formally standardised the SI name 'femtometer', the fermi remains in widespread informal use.

Where it is used

Fermis are used to express nuclear sizes, hadron radii, and characteristic length scales in particle physics. Functionally identical to the femtometer.

When and where it was developed

Named after Enrico Fermi; in informal use from the 1950s; officially equivalent to the SI femtometer.

Bohr Radius to Fermi conversion formula

The relationship between bohr radii and fermis:

1 a₀ = 52917.7210903 F
1 F = 1.889726e-5 a₀

To convert bohr radii to fermis, multiply the value in bohr radii by 52917.7210903. To reverse, multiply fermis by 1.889726e-5.

How to use this converter

Type a value into the calculator. The result in fermis updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Fermi to Bohr Radius converter for the reverse direction.

Step-by-step: convert bohr radii to fermis

  1. Write down the value in bohr radii (a₀).
  2. Multiply that value by the factor 52917.7210903.
  3. The product is the equivalent value in fermis (F).
  4. To reverse, multiply the fermi value by 1.889726e-5.

Worked examples

Example 1 — Convert 1 a₀ to F:
1 × 52917.7210903 = 52917.7210903 F

Example 2 — Convert 100 a₀ to F:
100 × 52917.7210903 = 5291772.109029999 F

Real-world example — Wavelengths across the spectrum

Optical and atomic-scale phenomena are routinely cross-converted between sub-micron units. A photon of wavelength 800 bohr radii can be re-expressed in fermis for direct comparison with another instrument's calibration data sheet.

800 a₀ × 52917.7210903 = 4.233418e+7 F

Real-world example — Molecular dimensions

The diameter of small molecular structures (around 2 bohr radii) is often converted into related sub-micron units when comparing measurements across different microscopy techniques or imaging modalities.

2 a₀ × 52917.7210903 = 105835.4421806 F

Bohr Radius to Fermi conversion table

Standard reference values for converting bohr radii to fermis:

Bohr Radius [a₀]Fermi [F]
0.01529.177210903
0.15291.77210903
152917.7210903
2105835.4421806
3158753.1632709
4211670.8843612
5264588.6054515
10529177.210903
201058354.4218059999
301587531.6327089998
402116708.8436119999
502645886.0545149995
1005291772.109029999
5002.645886e+7
10005.291772e+7

Frequently asked questions

How many fermis is 1 bohr radius?
1 bohr radius equals 52917.7210903 fermi.
How do I convert bohr radii to fermis?
Multiply the value in bohr radii by 52917.7210903 to get fermis.
How do I convert fermis back to bohr radii?
Multiply the value in fermis by 1.889726e-5, or use the Fermi to Bohr Radius converter.
How many fermis is 100 bohr radii?
100 bohr radii equals 5291772.109029999 fermis, because 100 × 52917.7210903 = 5291772.109029999.

Convert Bohr Radius to other length units

Show all Bohr Radius conversions

Sources & references

Conversion factor (1 a₀ = 52917.7210903 F) verified against the following authoritative sources:

Results are provided for general reference. Verify critical measurements against an authoritative standard.