Convert Foot to Earth's Equatorial Radius
Convert feet to earth's equatorial radii instantly. 1 foot = 4.778825e-8 earth's equatorial radius — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Earth's Equatorial Radius to Foot converter for the reverse conversion.
Units explained
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.
Earth's Equatorial Radius
Earth's equatorial radius is the distance from the planet's center to its surface at the equator, defined as exactly 6,378,137 meters by the WGS84 geodetic reference system.
The WGS84 (World Geodetic System 1984) defines Earth's reference ellipsoid for use in GPS and global cartography. The 6,378,137 m equatorial value was determined through satellite and ground geodetic measurements consolidated in 1984.
WGS84's equatorial radius is the standard reference for GPS, satellite imagery, geographic information systems, and aviation navigation. It defines the 'a' parameter of Earth's reference ellipsoid in coordinate transformations.
WGS84 reference ellipsoid adopted in 1984 by the US Department of Defense; subsequently adopted globally for GPS and civilian geodesy.
Foot to Earth's Equatorial Radius conversion formula
The relationship between feet and earth's equatorial radii:
To convert feet to earth's equatorial radii, multiply the value in feet by 4.778825e-8. To reverse, multiply earth's equatorial radii by 2.092565e+7.
How to use this converter
Type a value into the calculator. The result in earth's equatorial 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 Earth's Equatorial Radius to Foot converter for the reverse direction.
Step-by-step: convert feet to earth's equatorial radii
- Write down the value in feet (ft).
- Multiply that value by the factor 4.778825e-8.
- The product is the equivalent value in earth's equatorial radii (R⊕,eq).
- To reverse, multiply the earth's equatorial radius value by 2.092565e+7.
Worked examples
Example 1 — Convert 1 ft to R⊕,eq:
1 × 4.778825e-8 = 4.778825e-8 R⊕,eq
Example 2 — Convert 100 ft to R⊕,eq:
100 × 4.778825e-8 = 4.778825e-6 R⊕,eq
Real-world example — Adult height conversion
A 1.8-foot-tall person measures a value in earth's equatorial radii that converts the height to the unit favoured by American forms, schools, or driver's licences. This is daily routine for anyone living between metric and imperial systems.
1.8 ft × 4.778825e-8 = 8.601885e-8 R⊕,eq
Real-world example — Fabric purchase length
Two feet of fabric equals a value in earth's equatorial radii essential for tailors and textile buyers sourcing material from international suppliers that quote in different units.
2 ft × 4.778825e-8 = 9.55765e-8 R⊕,eq
Real-world example — Maritime depth conversion
A 10-foot sounding depth converts cleanly into earth's equatorial radii. Recreational divers and sailors translate between the two units whenever they read legacy charts against modern depth-sounder displays.
10 ft × 4.778825e-8 = 4.778825e-7 R⊕,eq
Foot to Earth's Equatorial Radius conversion table
Standard reference values for converting feet to earth's equatorial radii:
| Foot [ft] | Earth's Equatorial Radius [R⊕,eq] |
|---|---|
| 0.01 | 4.778825e-10 |
| 0.1 | 4.778825e-9 |
| 1 | 4.778825e-8 |
| 2 | 9.55765e-8 |
| 3 | 1.433647e-7 |
| 4 | 1.91153e-7 |
| 5 | 2.389412e-7 |
| 10 | 4.778825e-7 |
| 20 | 9.55765e-7 |
| 30 | 1.433647e-6 |
| 40 | 1.91153e-6 |
| 50 | 2.389412e-6 |
| 100 | 4.778825e-6 |
| 500 | 2.389412e-5 |
| 1000 | 4.778825e-5 |
Frequently asked questions
How many earth's equatorial radii is 1 foot?
How do I convert feet to earth's equatorial radii?
How do I convert earth's equatorial radii back to feet?
How many earth's equatorial radii is 100 feet?
Popular length unit conversions
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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 = 4.778825e-8 R⊕,eq) 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 Astronomical Union — System of Astronomical Constants
The IAU defines astronomical units including the AU (149597870700 m exactly) light-year and parsec used in astronomy and astrophysics.