Convert Centimeter to Megameter
Convert centimeters to megameters instantly. 1 centimeter = 1e-8 megameter — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Megameter to Centimeter converter for the reverse conversion.
Units explained
Centimeter
A centimeter is a metric unit of length equal to one hundredth of a meter (1/100 m). It is one of the most commonly used SI sub-units in daily life, especially for measuring small objects, body dimensions, paper sizes, and short distances.
The centimeter emerged from the French metric system established by the French Academy of Sciences in 1793. The metric system introduced decimal-based prefixes (milli-, centi-, deci-, deca-, hecto-, kilo-) to create proportional sub-units of the meter.
Centimeters are the standard unit for everyday measurement in nearly every country outside the United States. They are used for body height, clothing sizes, rainfall, paper formats (A4 is 21 × 29.7 cm), screen dimensions, and most consumer product specifications.
Developed in France during the late 18th century as part of the metric system designed by the French Academy of Sciences. Formally adopted in France in 1795 and ratified internationally through the Metre Convention signed in Paris in 1875.
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.
Centimeter to Megameter conversion formula
The relationship between centimeters and megameters:
To convert centimeters to megameters, multiply the value in centimeters by 1e-8. To reverse, multiply megameters by 1e+8.
How to use this converter
Type a value into the calculator. The result in megameters updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Megameter to Centimeter converter for the reverse direction.
Step-by-step: convert centimeters to megameters
- Write down the value in centimeters (cm).
- Multiply that value by the factor 1e-8.
- The product is the equivalent value in megameters (Mm).
- To reverse, multiply the megameter value by 1e+8.
Worked examples
Example 1 — Convert 1 cm to Mm:
1 × 1e-8 = 1e-8 Mm
Example 2 — Convert 100 cm to Mm:
100 × 1e-8 = 1e-6 Mm
Real-world example — Hardware-scale dimensions
A 10-centimeter fastener or component is about as long as a thumbnail. Mechanics and DIY enthusiasts convert between centimeters and megameters daily when mixing metric and imperial tools.
10 cm × 1e-8 = 1e-7 Mm
Real-world example — Postcard and small-object dimensions
A postcard is about 5 centimeters wide. Converting to megameters is essential for international postal addressing forms that ask for dimensions in different units across countries.
5 cm × 1e-8 = 5e-8 Mm
Real-world example — Ruler-scale measurements
A 30-centimeter school ruler converts cleanly to megameters — useful when buying a desk accessory from a retailer whose product specs use a different unit.
30 cm × 1e-8 = 3e-7 Mm
Centimeter to Megameter conversion table
Standard reference values for converting centimeters to megameters:
| Centimeter [cm] | Megameter [Mm] |
|---|---|
| 0.01 | 1e-10 |
| 0.1 | 1e-9 |
| 1 | 1e-8 |
| 2 | 2e-8 |
| 3 | 3e-8 |
| 4 | 4e-8 |
| 5 | 5e-8 |
| 10 | 1e-7 |
| 20 | 2e-7 |
| 30 | 3e-7 |
| 40 | 4e-7 |
| 50 | 5e-7 |
| 100 | 1e-6 |
| 500 | 5e-6 |
| 1000 | 1e-5 |
Frequently asked questions
How many megameters is 1 centimeter?
How do I convert centimeters to megameters?
How do I convert megameters back to centimeters?
How many megameters is 100 centimeters?
Popular length unit conversions
Convert Centimeter to other length units
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Metric / SI (17 units)
Imperial / US Customary (27 units)
Nautical (1 units)
Astronomical (9 units)
Atomic / Physics (6 units)
Typographic (3 units)
Sources & references
Conversion factor (1 cm = 1e-8 Mm) 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.