Convert Megameter to Dekameter
Convert megameters to dekameters instantly. 1 megameter = 100000 dekameter — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Dekameter 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.
Dekameter
A dekameter (also spelled decameter) is a metric unit of length equal to ten meters (10 m). It is one of the less commonly used SI prefix units and primarily appears in agricultural, surveying, and atmospheric contexts.
The dekameter was defined alongside the meter when France adopted the metric system in 1795, using the standard SI prefix deca- (from Greek deka, ten) to denote a multiplication by ten.
Dekameters are used in some European agricultural contexts (parcel sizes, field measurements), atmospheric science (cloud heights), and certain track and field events. Modern usage is uncommon outside specialised technical fields.
Adopted in 1795 in France; ratified through the Metre Convention of 1875; remains a recognised SI prefix unit although informally superseded by the more common meter and hectometer in everyday surveying.
Megameter to Dekameter conversion formula
The relationship between megameters and dekameters:
To convert megameters to dekameters, multiply the value in megameters by 100000. To reverse, multiply dekameters by 1e-5.
How to use this converter
Type a value into the calculator. The result in dekameters updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Dekameter to Megameter converter for the reverse direction.
Step-by-step: convert megameters to dekameters
- Write down the value in megameters (Mm).
- Multiply that value by the factor 100000.
- The product is the equivalent value in dekameters (dam).
- To reverse, multiply the dekameter value by 1e-5.
Worked examples
Example 1 — Convert 1 Mm to dam:
1 × 100000 = 100000 dam
Example 2 — Convert 100 Mm to dam:
100 × 100000 = 1e+7 dam
Megameter to Dekameter conversion table
Standard reference values for converting megameters to dekameters:
| Megameter [Mm] | Dekameter [dam] |
|---|---|
| 0.01 | 1000 |
| 0.1 | 10000 |
| 1 | 100000 |
| 2 | 200000 |
| 3 | 300000 |
| 4 | 400000 |
| 5 | 500000 |
| 10 | 1000000 |
| 20 | 2000000 |
| 30 | 3000000 |
| 40 | 4000000 |
| 50 | 5000000 |
| 100 | 1e+7 |
| 500 | 5e+7 |
| 1000 | 1e+8 |
Frequently asked questions
How many dekameters is 1 megameter?
How do I convert megameters to dekameters?
How do I convert dekameters back to megameters?
How many dekameters is 100 megameters?
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Sources & references
Conversion factor (1 Mm = 100000 dam) 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.