# Convert kilometers to millimeters

Enter the number of kilometers you want to convert to millimeters in the text box below. The conversion to length in millimeters will update as you type.

kilometers (km)
1 kilometers = 1,000,000 millimeters

## Precise decimal and fraction answers

The conversion in millimeters rounded to six significant decimal places is 1 km = 1,000,000.000000 mm. The precise fraction answer is 1,000,000 0/1 mm.

### Decimal Precision

Conversion from one to ten decimal places

• 1 km = 1,000,000.0 mm
• 1 km = 1,000,000.00 mm
• 1 km = 1,000,000.000 mm
• 1 km = 1,000,000.0000 mm
• 1 km = 1,000,000.00000 mm
• 1 km = 1,000,000.000000 mm
• 1 km = 1,000,000.0000000 mm
• 1 km = 1,000,000.00000000 mm
• 1 km = 1,000,000.000000000 mm
• 1 km = 1,000,000.0000000000 mm

## How many millimeters are in a kilometer?

There are 1,000,000 millimeters in one kilometer. A kilometer is 1,000,000 times longer than a millimeter. A millimeter is 0.00010% of a kilometer

## Kilometers to millimeters conversion factor and formulas

Formula

The conversion factor between kilometers and millimeters is 1,000,000. This represents the ratio of millimeters per one kilometer. To calculate the value in millimeters, we can either multiply by the conversion factor or divide by its inverse.

### Multiplication

To convert from kilometers to millimeters, multiply kilometers by 1,000,000.
The formula is expressed as:
km × 1,000,000 = mm

### Division

Alternatively we can divide by the inverse conversion factor to get the same result.
The inverse of 1,000,000 is 1/1,000,000 or 0. To convert from kilometers to millimeters, divide kilometers by 0.
The formula is expressed as:
km ÷ 0 = mm

A conversion from kilometers to millimeters are units within in the metric (SI) or SI compatible systems.

SI Unit

Within the SI (metric) system of measurement, the kilometer is officially defined as being equal to 1,000 meters. It is commonly used as measurement for geographic distances in similar circumstances where a mile would be used in the U.S. Internationally it is spelled 'kilometre' whereas the U.S. spells it 'kilometer'. The symbol for a kilometer is km however k is sometimes used.

SI Unit

Within the SI (metric) system of measurement, the millimeter is officially defined as one thousandth (1/1,000) of a meter. It is commonly used when measuring very short lengths. Internationally it is spelled 'millimetre' whereas the U.S. spells it 'millimeter'. The symbol for millimeters is mm.

## Reverse this conversion

Convert from millimeters to kilometers instead.

## 1 kilometers to other length units

### Metric

• 1 km = 1 km
• 1 km = 1,000 m
• 1 km = 10,000 dm
• 1 km = 100,000 cm
• 1 km = 1,000,000 mm
• 1 km = 1×109 µ
• 1 km = 1×1012 nm

### Imperial/U.S.

• 1 km = 0.621 mi
• 1 km = 1,093.613 yd
• 1 km = 3,280.84 ft
• 1 km = 39,370.079 in

## References and Citations

1. International Bureau of Weights and Measures (BIPM) The International System of Units (SI)

## Kilometers to millimeters conversion table

km mm
1 km 1,000,000 mm
2 km 2,000,000 mm
3 km 3,000,000 mm
4 km 4,000,000 mm
5 km 5,000,000 mm
6 km 6,000,000 mm
7 km 7,000,000 mm
8 km 8,000,000 mm
9 km 9,000,000 mm
10 km 1×107 mm
km mm
20 km 2×107 mm
30 km 3×107 mm
40 km 4×107 mm
50 km 5×107 mm
60 km 6×107 mm
70 km 7×107 mm
80 km 8×107 mm
90 km 9×107 mm
100 km 1×108 mm
1,000 km 1×109 mm