Convert Megameter to Kilometer
Convert megameters to kilometers instantly. 1 megameter = 1000 kilometer — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Kilometer to Megameter converter for the reverse conversion.
Units explained
Megameter
A megameter is a metric unit of length equal to one million meters (1×10⁶ m, or 1,000 km). It is occasionally used in geophysics and astronomy when expressing planetary-scale distances in SI units.
The megameter uses the SI prefix mega- (from Greek megas, great), adopted by the CGPM in 1960 to denote multiplication by one million.
Megameters appear in geophysics (Earth's mean radius is 6.371 Mm), planetary science, and large-scale civil engineering planning. The unit is less common than the kilometer for everyday geographic distances.
SI prefix mega- adopted in 1960; the megameter is the standard SI prefix unit for distances comparable to planetary radii.
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.
Megameter to Kilometer conversion formula
The relationship between megameters and kilometers:
To convert megameters to kilometers, multiply the value in megameters by 1000. To reverse, multiply kilometers by 0.001.
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 Megameter converter for the reverse direction.
Step-by-step: convert megameters to kilometers
- Write down the value in megameters (Mm).
- Multiply that value by the factor 1000.
- The product is the equivalent value in kilometers (km).
- To reverse, multiply the kilometer value by 0.001.
Worked examples
Example 1 — Convert 1 Mm to km:
1 × 1000 = 1000 km
Example 2 — Convert 100 Mm to km:
100 × 1000 = 100000 km
Megameter to Kilometer conversion table
Standard reference values for converting megameters to kilometers:
| Megameter [Mm] | Kilometer [km] |
|---|---|
| 0.01 | 10 |
| 0.1 | 100 |
| 1 | 1000 |
| 2 | 2000 |
| 3 | 3000 |
| 4 | 4000 |
| 5 | 5000 |
| 10 | 10000 |
| 20 | 20000 |
| 30 | 30000 |
| 40 | 40000 |
| 50 | 50000 |
| 100 | 100000 |
| 500 | 500000 |
| 1000 | 1000000 |
Frequently asked questions
How many kilometers is 1 megameter?
How do I convert megameters to kilometers?
How do I convert kilometers back to megameters?
How many kilometers is 100 megameters?
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Sources & references
Conversion factor (1 Mm = 1000 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.