Cubic metric volume unit.
Cubic Kilometers to Cubic Megameters Converter — km3 to Mm3
Convert Cubic Kilometer (km3) to Cubic Megameter (Mm3) using the exact conversion factor (1 cubic kilometer = 1e-9 cubic megameter). See the formula, worked examples, and conversion table.
Cubic Kilometers to Cubic Megameters converter
Converter
Volume Converter
Convert metric, US customary, imperial, cooking, dry, and industrial volume units.
Context values
Some unit families need one extra value for a physically accurate result.
Cubic metric volume unit.
Result = input x 1e+9 / 1e+18.
Volume uses the cubic meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Cubic Kilometers to Cubic Megameters
Cubic Kilometer and Cubic Megameter appear side by side at fuel pumps and on beverage labels, since the US measures liquids in gallons while most of the world uses liters. Both are cubic metric volume unit units.
Formula
cubic megameters = cubic kilometers × 1e-9
This factor comes from each unit's defined relationship to the category's base unit: 1 cubic kilometer equals 1000000000 base units, and 1 cubic megameter equals 1e+18 base units, so dividing one by the other gives the direct cubic kilometer-to-cubic megameter factor of 1e-9.
Simple example
1 km3 × 1e-9 = 1e-9 Mm3
1 cubic kilometer = 1e-9 cubic megameters.
Real-world example
10 km3 × 1e-9 = 1e-8 Mm3
10 cubic kilometers = 1e-8 cubic megameters.
Conversion table
| Cubic Kilometer (km3) | Cubic Megameter (Mm3) |
|---|---|
| 1 km3 | 1e-9 Mm3 |
| 5 km3 | 5e-9 Mm3 |
| 10 km3 | 1e-8 Mm3 |
| 25 km3 | 2.5e-8 Mm3 |
| 50 km3 | 5e-8 Mm3 |
| 100 km3 | 1e-7 Mm3 |
Reverse conversion: Cubic Megameter to Cubic Kilometer
1e-9 Mm3 × 1000000000 = 1 km3
1e-9 cubic megameters = 1 cubic kilometers.
cubic kilometers = cubic megameters × 1000000000
For a page dedicated to this direction, see Cubic Megameter to Cubic Kilometer.
Understanding the Cubic Kilometer (km3)
Cubic metric volume unit.
Understanding the Cubic Megameter (Mm3)
Cubic metric volume unit.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many cubic megameters are in 1 cubic kilometer?
1 cubic kilometer equals 1e-9 cubic megameters, using the exact defined conversion factor rather than an estimate.
How do I convert cubic kilometer to cubic megameter?
Multiply the cubic kilometer value by 1e-9. The converter above does this instantly to whatever precision you set.
How do I convert cubic megameter back to cubic kilometer?
Use the reverse factor: 1 cubic megameter equals 1,000,000,000 cubic kilometers. You can also use the swap control in the converter above to flip the direction instantly.
What is a cubic kilometer?
Cubic Kilometer (km3) is a unit of volume.
What is a cubic megameter?
Cubic Megameter (Mm3) is a unit of volume.
Is the cubic kilometer to cubic megameter conversion exact?
Yes. Both cubic kilometer and cubic megameter are defined by fixed standards rather than physical artifacts, so the factor of 1e-9 used above is exact to as many digits as you choose to display.