Conversion formula

The conversion factor from kilometers to centimeters is 100000, which means that 1 kilometer is equal to 100000 centimeters:

1 km = 100000 cm

To convert 21 kilometers into centimeters we have to multiply 21 by the conversion factor in order to get the length amount from kilometers to centimeters. We can also form a simple proportion to calculate the result:

1 km → 100000 cm

21 km → L_(cm)

Solve the above proportion to obtain the length L in centimeters:

L_(cm) = 21 km × 100000 cm

L_(cm) = 2100000 cm

The final result is:

21 km → 2100000 cm

We conclude that 21 kilometers is equivalent to 2100000 centimeters:

21 kilometers = 2100000 centimeters

Alternative conversion

We can also convert by utilizing the inverse value of the conversion factor. In this case 1 centimeter is equal to 4.7619047619048E-7 × 21 kilometers.

Another way is saying that 21 kilometers is equal to 1 ÷ 4.7619047619048E-7 centimeters.

Approximate result

For practical purposes we can round our final result to an approximate numerical value. We can say that twenty-one kilometers is approximately two million one hundred thousand centimeters:

21 km ≅ 2100000 cm

An alternative is also that one centimeter is approximately zero times twenty-one kilometers.

Conversion table

kilometers to centimeters chart

For quick reference purposes, below is the conversion table you can use to convert from kilometers to centimeters