Earth's Equatorial Radius to Kilometer Converter
Unit Converter
Instant · Precise · Universal
32 units available
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How to Convert Earth's Equatorial Radius to Kilometer
To convert Earth radii to meters: multiply by 6,378,137.
R⊕(eq) = 6,378,137 m = 6,378.137 km. Earth's oblateness = (R_eq − R_pol)/R_eq ≈ 1/298.257.
For example, 1 Earth's Equatorial Radius (R⊕ (eq)) = 6378.137 Kilometer (km).
Earth's Equatorial Radius to Kilometer — Common Values
| Earth's Equatorial Radius (R⊕ (eq)) | Kilometer (km) |
|---|---|
| 0.1 | 637.8137 |
| 0.5 | 3189.0685 |
| 1 | 6378.137 |
| 2 | 12756.274 |
| 5 | 31890.685 |
| 10 | 63781.37 |
| 25 | 159453.425 |
| 50 | 318906.85 |
| 100 | 637813.7 |
| 500 | 3189068.5 |
| 1000 | 6378137 |
About Earth's Equatorial Radius (R⊕ (eq))
Definition
The Earth's equatorial radius is the distance from Earth's center to the equator, approximately 6,378.137 km.
Mathematical Relationship
R⊕(eq) = 6,378,137 m = 6,378.137 km. Earth's oblateness = (R_eq − R_pol)/R_eq ≈ 1/298.257.
Conversion Formula
To convert Earth radii to meters: multiply by 6,378,137.
Practical Applications
GPS calculations, satellite orbit determination, map projections, and geophysical modeling.
Interesting Facts
Earth is not a perfect sphere — the equatorial radius is about 21 km (0.3%) larger than the polar radius due to rotational flattening.
Common Mistakes
Using the equatorial radius as if Earth were a sphere — for precision, you must account for the oblate spheroid shape.
Educational Tips
Earth's equatorial radius (6,378 km) vs. polar radius (6,357 km) shows the planet bulges at the equator due to spinning.
About Kilometer (km)
Definition
The kilometer is a unit of length equal to 1,000 meters, commonly used to express distances between geographic locations.
Mathematical Relationship
1 km = 1,000 m = 100,000 cm = 0.621371 miles. There are 1.60934 km in one mile.
Conversion Formula
To convert km to miles: multiply by 0.621371. To convert miles to km: multiply by 1.60934.
Practical Applications
Road signs, marathon distances (42.195 km), GPS navigation, geographic mapping, and aviation flight distances.
Interesting Facts
A marathon is 42.195 km. The circumference of Earth is approximately 40,075 km at the equator.
Common Mistakes
Assuming 1 km = 1 mile. A kilometer is only about 62% of a mile. Also, speed: 100 km/h ≈ 62 mph, not 100 mph.
Educational Tips
Quick approximation: multiply km by 0.6 to estimate miles, or multiply miles by 1.6 for km.