Convert Earth's Equatorial Radius to Kilometer
Convert earth's equatorial radii to kilometers instantly. 1 earth's equatorial radius = 6378.137 kilometer — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Kilometer to Earth's Equatorial Radius converter for the reverse conversion.
Units explained
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.
Kilometer
A kilometer is a metric unit of length equal to one thousand meters. It is the standard unit for measuring road distances, geographic distances, and other large-scale measurements in metric countries.
The kilometer was defined alongside the meter in 1795 using the standard SI prefix kilo- (from Greek chilioi, "thousand"), denoting one thousand units.
Kilometers are used worldwide (except the United States and a few others) for road signage, geographic distance, athletic events, and scientific distances at planetary scale. Speed limits in most countries are given in km/h.
Adopted 1795 in France as part of the original metric system; the kilometer became the global standard for road and geographic distance through the 19th and 20th century metric adoption.
Earth's Equatorial Radius to Kilometer conversion formula
The relationship between earth's equatorial radii and kilometers:
To convert earth's equatorial radii to kilometers, multiply the value in earth's equatorial radii by 6378.137. To reverse, multiply kilometers by 0.0001567856.
How to use this converter
Type a value into the calculator. The result in kilometers updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Kilometer to Earth's Equatorial Radius converter for the reverse direction.
Step-by-step: convert earth's equatorial radii to kilometers
- Write down the value in earth's equatorial radii (R⊕,eq).
- Multiply that value by the factor 6378.137.
- The product is the equivalent value in kilometers (km).
- To reverse, multiply the kilometer value by 0.0001567856.
Worked examples
Example 1 — Convert 1 R⊕,eq to km:
1 × 6378.137 = 6378.137 km
Example 2 — Convert 100 R⊕,eq to km:
100 × 6378.137 = 637813.7 km
Earth's Equatorial Radius to Kilometer conversion table
Standard reference values for converting earth's equatorial radii to kilometers:
| Earth's Equatorial Radius [R⊕,eq] | Kilometer [km] |
|---|---|
| 0.01 | 63.78137 |
| 0.1 | 637.8137 |
| 1 | 6378.137 |
| 2 | 12756.274 |
| 3 | 19134.411 |
| 4 | 25512.548 |
| 5 | 31890.685 |
| 10 | 63781.37 |
| 20 | 127562.74 |
| 30 | 191344.11 |
| 40 | 255125.48 |
| 50 | 318906.85 |
| 100 | 637813.7 |
| 500 | 3189068.5 |
| 1000 | 6378137 |
Frequently asked questions
How many kilometers is 1 earth's equatorial radius?
How do I convert earth's equatorial radii to kilometers?
How do I convert kilometers back to earth's equatorial radii?
How many kilometers is 100 earth's equatorial radii?
Popular length unit conversions
Convert Earth's Equatorial Radius to other length units
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Metric / SI (4 units)
Imperial / US Customary (4 units)
Astronomical (8 units)
Sources & references
Conversion factor (1 R⊕,eq = 6378.137 km) 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.