mm to km Converter

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Convert millimeters to kilometers using the SI chain 1 km = 1,000 m and 1 m = 1,000 mm, so 1 mm = 0.000001 km. The most common use is rolling up huge mm-precision counts from a CNC log, conveyor belt counter or rainfall millimeter total into a single kilometer figure for reporting. Browser-local.

Millimeter (mm)
Kilometer (km)

Millimeter (mm) → Kilometer (km)

Quick reference table

Millimeter (mm)Kilometer (km)
1 mm0 km
2 mm0 km
5 mm0 km
10 mm0 km
25 mm0 km
50 mm0.0001 km
100 mm0.0001 km

Glossary

Millimeter (mm)

A millimeter is one thousandth of a meter (1 mm = 0.1 cm = 0.03937 inch). It is the default fine-resolution unit on rulers, mechanical drawings, electronics PCBs and rainfall gauges. Ten millimeters make a centimeter; one inch contains exactly 25.4 millimeters by international agreement since 1959.

Kilometer (km)

A kilometer is one thousand meters (1 km = 0.6214 mile = 0.5400 nautical mile). It is the standard road-distance unit everywhere except the United States, the United Kingdom and a handful of other countries. Marathon distances, highway speeds and geographic distances on most maps use kilometers.

Metric system (SI)

The metric system is a decimal system of measurement built around the meter for length, the kilogram for mass and the second for time, with multiples and submultiples expressed as powers of ten (millimeter, centimeter, kilometer). Adopted in France in 1799 and codified internationally as the International System of Units (SI) in 1960, it is now the official measurement system in nearly every country and the standard in science and engineering worldwide.

Imperial / US Customary system

The imperial system is the historical English system of weights and measures whose length units are the inch, foot, yard and mile (12 in = 1 ft, 3 ft = 1 yd, 1,760 yd = 1 mi). Codified by the British Weights and Measures Act of 1824 and aligned with US Customary by the international yard-and-pound agreement of 1959 (1 inch = 25.4 mm exactly), it is still used in the United States, the United Kingdom and a handful of other countries for everyday distances.

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