CM to KM Converter
Enter centimeters or kilometers. Paste a cm or km suffix to set the direction automatically.
Exact length relationship: 1 km = 100,000 cm
ASCII and Unicode fractions such as 1/2 and 1½ are supported. A pasted cm, centimeter, centimetre, km, kilometer, or kilometre suffix sets the direction.
Copy manually
How to convert centimeters to kilometers
Kilometers = centimeters ÷ 100,000. For example, 250,000 cm ÷ 100,000 = 2.5 km.
Common cm to km values
| Centimeters | Kilometers |
|---|---|
| 1 cm | 0.00001 km |
| 100 cm | 0.001 km |
| 1,000 cm | 0.01 km |
| 10,000 cm | 0.1 km |
| 100,000 cm | 1 km |
| 250,000 cm | 2.5 km |
How to convert kilometers to centimeters
Centimeters = kilometers × 100,000. A length of 1.5 km therefore equals 150,000 cm. Swap carries the unrounded result into the other direction.
Why the 100,000-to-1 factor is exact
In SI prefixes, centi means 10⁻² and kilo means 10³. Their difference is 10⁵, so 1 kilometer equals exactly 100,000 centimeters. Display rounding changes only the visible number, not this factor.
Pasted units, fractions, and small scientific results
You can paste cm, centimeter, centimetre, km, kilometer, or kilometre in singular or plural form. The suffix sets the direction automatically. Decimals and ASCII or Unicode fractions such as 1/2, ½, and 1½ are accepted. Tiny nonzero results use scientific notation instead of disappearing as zero.
Linear length only
This focused converter does not calculate area, volume, speed, map scale, or drawing scale. It does not add a precision selector or batch mode, and the reverse conversion stays on this same page.
Frequently asked questions
How many centimeters are in a kilometer?
There are exactly 100,000 centimeters in 1 kilometer.
What is the formula for cm to km?
Divide centimeters by 100,000. For example, 250,000 cm ÷ 100,000 = 2.5 km.
How do I convert km back to cm?
Multiply kilometers by 100,000. For example, 1.5 km × 100,000 = 150,000 cm.
Can I paste centimetres or kilometres?
Yes. The converter recognizes cm, km, and American or British spellings of centimeter and kilometer. A pasted suffix overrides the selected direction.
Does this convert square or cubic units?
No. This page converts linear length only. Square and cubic units use different factors and are rejected rather than guessed.
Why does a very small result use scientific notation?
Scientific notation keeps a tiny nonzero answer visible when a fixed decimal display would look like zero. A rounded display is marked with ≈.