Millimeters to Meters Converter

About the mm to m calculation

One millimeter is exactly 0.001 meters, so converting between them is a single multiplication. Enter any value above and the result updates as you type. The standard fine unit on engineering drawings and rainfall figures. The SI base unit of length, defined by the distance light travels in 1/299,792,458 of a second.

Formula

m = mm × 0.001

1 mm = 0.001 m
1 m = 1,000 mm

Worked example

To convert 100 mm, multiply by 0.001: 100 × 0.001 = 0.1 m.

Frequently asked questions

How many meters are in a millimeter?

There are 0.001 meters in one millimeter. To convert any amount, multiply the number of millimeters by 0.001.

How do I convert meters back to millimeters?

Divide instead of multiplying, or equivalently multiply by 1,000. One meter is 1,000 millimeters.

Is this conversion exact?

Yes. Since the international agreement of 1959, the relationship between millimeters and meters is defined exactly rather than measured, so the only rounding here is in how many decimal places we show.

Where is each of these units used?

Millimeters: the standard fine unit on engineering drawings and rainfall figures. Meters: the SI base unit of length, defined by the distance light travels in 1/299,792,458 of a second.

Sources

• NIST Special Publication 811 — Guide for the Use of the International System of Units