Convert Gigameter to Kilometer
Convert gigameters to kilometers instantly. 1 gigameter = 1000000 kilometer — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Kilometer to Gigameter converter for the reverse conversion.
Units explained
Gigameter
A gigameter is a metric unit of length equal to one billion meters (1×10⁹ m). It is most often used in astronomy and astrophysics when expressing distances within the inner solar system.
The gigameter uses the SI prefix giga- (from Greek gigas, giant), adopted by the CGPM in 1960 to denote multiplication by one billion (10⁹).
Gigameters are used to express distances such as the Sun's diameter (~1.39 Gm), the Earth–Moon distance (~0.384 Gm), and similar inner-solar-system scales. Astronomical units and light-seconds are also common for these distances.
SI prefix giga- adopted in 1960; the gigameter became standard in astronomy for sub-AU distances by the late 20th century.
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.
Gigameter to Kilometer conversion formula
The relationship between gigameters and kilometers:
To convert gigameters to kilometers, multiply the value in gigameters by 1000000. To reverse, multiply kilometers by 1e-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 Gigameter converter for the reverse direction.
Step-by-step: convert gigameters to kilometers
- Write down the value in gigameters (Gm).
- Multiply that value by the factor 1000000.
- The product is the equivalent value in kilometers (km).
- To reverse, multiply the kilometer value by 1e-6.
Worked examples
Example 1 — Convert 1 Gm to km:
1 × 1000000 = 1000000 km
Example 2 — Convert 100 Gm to km:
100 × 1000000 = 1e+8 km
Gigameter to Kilometer conversion table
Standard reference values for converting gigameters to kilometers:
| Gigameter [Gm] | Kilometer [km] |
|---|---|
| 0.01 | 10000 |
| 0.1 | 100000 |
| 1 | 1000000 |
| 2 | 2000000 |
| 3 | 3000000 |
| 4 | 4000000 |
| 5 | 5000000 |
| 10 | 1e+7 |
| 20 | 2e+7 |
| 30 | 3e+7 |
| 40 | 4e+7 |
| 50 | 5e+7 |
| 100 | 1e+8 |
| 500 | 5e+8 |
| 1000 | 1e+9 |
Frequently asked questions
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Sources & references
Conversion factor (1 Gm = 1000000 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.