Convert Classical Electron Radius to Foot
Convert classical electron radii to feet instantly. 1 classical electron radius = 9.245211e-15 foot — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Foot to Classical Electron Radius converter for the reverse conversion.
Units explained
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.
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.
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.
Concept dates to the early 20th-century classical electromagnetism; CODATA 2018 provides the current reference value.
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.
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.
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.
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.
Classical Electron Radius to Foot conversion formula
The relationship between classical electron radii and feet:
To convert classical electron radii to feet, multiply the value in classical electron radii by 9.245211e-15. To reverse, multiply feet by 1.081641e+14.
How to use this converter
Type a value into the calculator. The result in feet updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Foot to Classical Electron Radius converter for the reverse direction.
Step-by-step: convert classical electron radii to feet
- Write down the value in classical electron radii (rₑ).
- Multiply that value by the factor 9.245211e-15.
- The product is the equivalent value in feet (ft).
- To reverse, multiply the foot value by 1.081641e+14.
Worked examples
Example 1 — Convert 1 rₑ to ft:
1 × 9.245211e-15 = 9.245211e-15 ft
Example 2 — Convert 100 rₑ to ft:
100 × 9.245211e-15 = 9.245211e-13 ft
Real-world example — Bridging nine orders of magnitude
500 million classical electron radii equals a value comfortably in the human-scale feet range. Physics problems that span this gap are common when comparing the wavelength of light to the path length of an experiment.
5e+8 rₑ × 9.245211e-15 = 4.622606e-6 ft
Real-world example — From sub-micron to human scale
One billion classical electron radii equals one foot — the conversion that drives home the gulf between atomic-scale features and everyday objects in physics curricula.
1e+9 rₑ × 9.245211e-15 = 9.245211e-6 ft
Classical Electron Radius to Foot conversion table
Standard reference values for converting classical electron radii to feet:
| Classical Electron Radius [rₑ] | Foot [ft] |
|---|---|
| 0.01 | 9.245211e-17 |
| 0.1 | 9.245211e-16 |
| 1 | 9.245211e-15 |
| 2 | 1.849042e-14 |
| 3 | 2.773563e-14 |
| 4 | 3.698084e-14 |
| 5 | 4.622606e-14 |
| 10 | 9.245211e-14 |
| 20 | 1.849042e-13 |
| 30 | 2.773563e-13 |
| 40 | 3.698084e-13 |
| 50 | 4.622606e-13 |
| 100 | 9.245211e-13 |
| 500 | 4.622606e-12 |
| 1000 | 9.245211e-12 |
Frequently asked questions
How many feet is 1 classical electron radius?
How do I convert classical electron radii to feet?
How do I convert feet back to classical electron radii?
How many feet is 100 classical electron radii?
Popular length unit conversions
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Metric / SI (4 units)
Imperial / US Customary (4 units)
Sources & references
Conversion factor (1 rₑ = 9.245211e-15 ft) verified against the following authoritative sources:
- BIPM — The International System of Units (SI Brochure 9th ed.)
Official BIPM publication defining the seven SI base units (including the meter) and the rules for their use. The global authority on units of measurement.
- NIST — Guide to the SI
US National Institute of Standards and Technology reference covering the SI base and derived units with definitions and usage rules for US technical practice.
- NIST Special Publication 811 — Guide for the Use of the International System of Units
Detailed NIST guide covering exact conversion factors between SI and US customary units along with formatting and rounding conventions.
- NIST — Refinement of values for the yard and pound (Federal Register 1959)
The treaty (signed by US
- International Hydrographic Organization — Resolution on the Nautical Mile
International authority that standardised the nautical mile at exactly 1852 m in 1929 — the value adopted worldwide for sea and air navigation.