Square Centimeters to Square Kilometers
An instant square centimeters-to-square kilometers converter, with the formula and a reference table below.
| Square Centimeters | Square Kilometers |
|---|---|
| 1 cm² | 1e-10 km² |
| 2 cm² | 2e-10 km² |
| 3 cm² | 3e-10 km² |
| 5 cm² | 5e-10 km² |
| 10 cm² | 1e-09 km² |
| 25 cm² | 2.5e-09 km² |
| 50 cm² | 5e-09 km² |
| 100 cm² | 1e-08 km² |
How to use
- Enter a value in the Square Centimeters field.
- The Square Kilometers figure appears immediately — no button to press.
- Typing in the Square Kilometers field converts back to Square Centimeters the same way.
- Use the reference table for the values that come up most often.
Square Centimeters to Square Kilometers formula
The factor from square centimeters to square kilometers is 1e-10.
km² = cm² × 1e-10
Why this factor: the square centimeter and the square kilometer are both defined against the square meter, so dividing one definition by the other gives 1e-10 directly. Both definitions are set out in full below.
To go the other way, divide by 1e-10 — or use the Square Kilometers to Square Centimeters converter, which is the same calculation reversed.
Worked example
Take 250 cm² and multiply by the factor 1e-10: the result is 2.5e-08 km².
250 cm² × 1e-10 = 2.5e-08 km²
The converter above does this for any value you type, in either direction.
What is a square centimeter?
A square centimeter is the area of a one-centimeter square.
Definition: Exactly 1×10⁻⁴ square meter — because 0.01 m squared is 0.0001 m².
Where it is used: Small surface areas, contact and cross-sectional areas, and pressure calculations.
What is a square kilometer?
A square kilometer is the area of a one-kilometer square — one million square meters.
Definition: Exactly 1×10⁶ square meters. Note it is the kilometer that is squared, not the prefix applied to a square meter.
Where it is used: City, national park and country areas, population density, and land cover statistics.
Square Centimeters vs Square Kilometers
The square centimeter and the square kilometer belong to the same family of units, so converting between them is usually a matter of shifting a decimal point or applying a small whole-number factor.
Frequently asked questions
How many square kilometers are in a square centimeter?
One square centimeter equals 1e-10 square kilometers.
What is the formula to convert square centimeters to square kilometers?
Multiply the number of square centimeters by 1e-10. To reverse it, divide by 1e-10 instead.
How do I convert square kilometers back to square centimeters?
Divide by 1e-10, which is the same as multiplying by 1e+10.
How many square kilometers are in 10 square centimeters?
10 cm² works out to 1e-09 km².
How is the square centimeter defined?
Exactly 1×10⁻⁴ square meter — because 0.01 m squared is 0.0001 m².