Length · Unit Converter

Convert Foot to Classical Electron Radius

Convert feet to classical electron radii instantly. 1 foot = 1.081641e+14 classical electron radius — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Classical Electron Radius to Foot 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

Imperial / US Customary

Foot

What is a foot?

A foot is an Imperial and US customary unit of length equal to 12 inches or exactly 0.3048 meters. It is the most commonly used unit of length in everyday measurement in the United States.

Origin of the foot

The foot's origin is literally the length of a human foot, used as a measurement standard since antiquity. The English foot was standardized at various points in history; the modern international foot (0.3048 m exactly) was fixed by the 1959 International Yard and Pound Agreement.

Where it is used

Feet are used in the US for body height, building dimensions, room sizes, road sign clearances, aviation altitude (feet above sea level), and most everyday distance estimation. The UK uses feet informally for height despite officially being metric.

When and where it was developed

Used since antiquity; standardized to 0.3048 m exactly by the International Yard and Pound Agreement of 1959. Aviation worldwide uses feet for altitude despite metric adoption elsewhere.

Atomic / Physics

Classical Electron Radius

What is a classical electron radius?

The classical electron radius is approximately 2.818×10⁻¹⁵ meters. It is the radius an electron would have if its mass were entirely electromagnetic and its charge distributed over its surface.

Origin of the classical electron radius

Defined classically in the early 20th century. The CODATA 2018 value of 2.8179403262×10⁻¹⁵ m is derived from the elementary charge, electron rest mass, and the Coulomb constant.

Where it is used

The classical electron radius appears in scattering theory (Thomson scattering cross-section), particle physics estimates, and historical electromagnetism. It is a calculational tool, not the actual size of an electron, which has no measured extent.

When and where it was developed

Concept dates to the early 20th-century classical electromagnetism; CODATA 2018 provides the current reference value.

Foot to Classical Electron Radius conversion formula

The relationship between feet and classical electron radii:

1 ft = 1.081641e+14 rₑ
1 rₑ = 9.245211e-15 ft

To convert feet to classical electron radii, multiply the value in feet by 1.081641e+14. To reverse, multiply classical electron radii by 9.245211e-15.

How to use this converter

Type a value into the calculator. The result in classical electron radii updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Classical Electron Radius to Foot converter for the reverse direction.

Step-by-step: convert feet to classical electron radii

  1. Write down the value in feet (ft).
  2. Multiply that value by the factor 1.081641e+14.
  3. The product is the equivalent value in classical electron radii (rₑ).
  4. To reverse, multiply the classical electron radius value by 9.245211e-15.

Worked examples

Example 1 — Convert 1 ft to rₑ:
1 × 1.081641e+14 = 1.081641e+14 rₑ

Example 2 — Convert 100 ft to rₑ:
100 × 1.081641e+14 = 1.081641e+16 rₑ

Real-world example — Meter to nanoscale

One foot equals one billion classical electron radii. Physics curricula use this conversion to teach orders of magnitude when introducing the electromagnetic spectrum.

1 ft × 1.081641e+14 = 1.081641e+14 rₑ

Real-world example — Human-scale to atomic dimensions

One foot equals one billion classical electron radii — the canonical metric conversion bridging everyday objects and atomic-scale features in physics, chemistry, and electronics.

1 ft × 1.081641e+14 = 1.081641e+14 rₑ

Foot to Classical Electron Radius conversion table

Standard reference values for converting feet to classical electron radii:

Foot [ft]Classical Electron Radius [rₑ]
0.011.081641e+12
0.11.081641e+13
11.081641e+14
22.163282e+14
33.244923e+14
44.326564e+14
55.408205e+14
101.081641e+15
202.163282e+15
303.244923e+15
404.326564e+15
505.408205e+15
1001.081641e+16
5005.408205e+16
10001.081641e+17

Frequently asked questions

How many classical electron radii is 1 foot?
1 foot equals 1.081641e+14 classical electron radius.
How do I convert feet to classical electron radii?
Multiply the value in feet by 1.081641e+14 to get classical electron radii.
How do I convert classical electron radii back to feet?
Multiply the value in classical electron radii by 9.245211e-15, or use the Classical Electron Radius to Foot converter.
How many classical electron radii is 100 feet?
100 feet equals 1.081641e+16 classical electron radii, because 100 × 1.081641e+14 = 1.081641e+16.

Convert Foot to other length units

Show all Foot conversions
Metric / SI (18 units)
Imperial / US Customary (26 units)
Nautical (1 units)
Astronomical (9 units)
Atomic / Physics (6 units)
Typographic (3 units)

Sources & references

Conversion factor (1 ft = 1.081641e+14 rₑ) verified against the following authoritative sources:

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