Convert Sun's Radius to Kilometer
Convert sun's radii to kilometers instantly. 1 sun's radius = 695700 kilometer — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Kilometer to Sun's Radius converter for the reverse conversion.
Units explained
Sun's Radius
The Sun's radius is approximately 695,700 km (6.957×10⁸ m), defined as the IAU 2015 nominal solar radius for use in stellar physics and exoplanet research.
The IAU (International Astronomical Union) Resolution B3 in 2015 defined a nominal solar radius of exactly 6.957×10⁸ m to serve as a stable reference, independent of actual measurement-uncertainty variations in the real Sun.
Solar radii are used in stellar physics, exoplanet characterisation, and any context where a star's size is expressed relative to the Sun. Most stellar radius measurements are quoted in solar-radius units rather than meters.
Defined exactly at 6.957×10⁸ m by IAU Resolution B3 in 2015.
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.
Sun's Radius to Kilometer conversion formula
The relationship between sun's radii and kilometers:
To convert sun's radii to kilometers, multiply the value in sun's radii by 695700. To reverse, multiply kilometers by 1.437401e-6.
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 Sun's Radius converter for the reverse direction.
Step-by-step: convert sun's radii to kilometers
- Write down the value in sun's radii (R☉).
- Multiply that value by the factor 695700.
- The product is the equivalent value in kilometers (km).
- To reverse, multiply the kilometer value by 1.437401e-6.
Worked examples
Example 1 — Convert 1 R☉ to km:
1 × 695700 = 695700 km
Example 2 — Convert 100 R☉ to km:
100 × 695700 = 6.957e+7 km
Sun's Radius to Kilometer conversion table
Standard reference values for converting sun's radii to kilometers:
| Sun's Radius [R☉] | Kilometer [km] |
|---|---|
| 0.01 | 6957 |
| 0.1 | 69570 |
| 1 | 695700 |
| 2 | 1391400 |
| 3 | 2087100 |
| 4 | 2782800 |
| 5 | 3478500 |
| 10 | 6957000 |
| 20 | 1.3914e+7 |
| 30 | 2.0871e+7 |
| 40 | 2.7828e+7 |
| 50 | 3.4785e+7 |
| 100 | 6.957e+7 |
| 500 | 3.4785e+8 |
| 1000 | 6.957e+8 |
Frequently asked questions
How many kilometers is 1 sun's radius?
How do I convert sun's radii to kilometers?
How do I convert kilometers back to sun's radii?
How many kilometers is 100 sun's radii?
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Metric / SI (4 units)
Imperial / US Customary (4 units)
Astronomical (8 units)
Sources & references
Conversion factor (1 R☉ = 695700 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.