## Conversion formula

The conversion factor from kilometers to millimeters is 1000000, which means that 1 kilometer is equal to 1000000 millimeters:

1 km = 1000000 mm

To convert 138 kilometers into millimeters we have to multiply 138 by the conversion factor in order to get the length amount from kilometers to millimeters. We can also form a simple proportion to calculate the result:

1 km → 1000000 mm

138 km → L(mm)

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

L(mm) = 138 km × 1000000 mm

L(mm) = 138000000 mm

The final result is:

138 km → 138000000 mm

We conclude that 138 kilometers is equivalent to 138000000 millimeters:

138 kilometers = 138000000 millimeters

## Alternative conversion

We can also convert by utilizing the inverse value of the conversion factor. In this case 1 millimeter is equal to 7.2463768115942E-9 × 138 kilometers.

Another way is saying that 138 kilometers is equal to 1 ÷ 7.2463768115942E-9 millimeters.

## Approximate result

For practical purposes we can round our final result to an approximate numerical value. We can say that one hundred thirty-eight kilometers is approximately one hundred thirty-eight million millimeters:

138 km ≅ 138000000 mm

An alternative is also that one millimeter is approximately zero times one hundred thirty-eight kilometers.

## Conversion table

### kilometers to millimeters chart

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

kilometers (km) millimeters (mm)
139 kilometers 139000000 millimeters
140 kilometers 140000000 millimeters
141 kilometers 141000000 millimeters
142 kilometers 142000000 millimeters
143 kilometers 143000000 millimeters
144 kilometers 144000000 millimeters
145 kilometers 145000000 millimeters
146 kilometers 146000000 millimeters
147 kilometers 147000000 millimeters
148 kilometers 148000000 millimeters