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Millimetres to metres

Multiply millimetres by 0.001 to get metres.

1 mm = 0.001 mBIPM SI
mm
0.5m

500 mm = 0.5 m

How to convert millimetres to metres

The metre is the SI base unit of length, defined since 1983 by fixing the speed of light at exactly 299 792 458 m/s. The millimetre is one thousandth of a metre (10⁻³ m).

Worked example — 500 mm: 500 × 0.001 = 0.5 m.

Millimetres to metres table

Common conversions. The reverse table is on metres to millimetres.
MillimetresMetres
1 mm0.001 m
10 mm0.01 m
100 mm0.1 m
250 mm0.25 m
500 mm0.5 m
1,000 mm1 m
2,000 mm2 m
5,000 mm5 m
10,000 mm10 m

Reverse and related

About millimetres and metres

Millimetre (mm)

1 mm = 0.001 m

Definition. One thousandth of a metre (10⁻³ m)

History and origin

The millimetre is one thousandth of a metre, defined with the rest of the decimal metric system in the 1790s. Its small size suits precise work.

Current use

Millimetres are used for rainfall, engineering tolerances, and the sizes of screws, hardware and printed parts.

Source: BIPM, The International System of Units (SI), 9th ed. (2019)

Metre (m)

1 m = 1,000 mm

Definition. The SI base unit of length, defined since 1983 by fixing the speed of light at exactly 299 792 458 m/s

History and origin

The metre was defined in 1793 as one ten-millionth of the distance from the equator to the North Pole, later realised as a platinum bar. Since 1983 it has been defined by fixing the speed of light at exactly 299 792 458 metres per second, tying it to a constant of nature rather than an object.

Current use

The metre is the base unit of length across the metric world, used for everything from building plans to sports fields; the United States is the main country that still measures everyday length in feet and inches.

Source: BIPM, The International System of Units (SI), 9th ed. (2019)

Where people use this

Millimetres: rainfall, engineering tolerances, screws and hardware. Metres: room and building dimensions, sports fields, fabric and rope. 1000 mm is exactly 1 m.

How we know this is right
The factor is fixed by the standards that define the units, not chosen — so it is exact, not a measurement:
1 m = 1,000 mm, so 1 mm = 1 ÷ 1,000 = 0.001 m.

Every value is carried to full double precision; the display is rounded.

Both units are defined in BIPM, The International System of Units (SI), 9th ed. (2019).

Questions people ask

How many mm make a metre?

It takes 1000 millimetres to make one metre.

How many metres is 500 mm?

500 mm is 0.5 metres.

What is 2500 mm in metres?

2500 mm is 2.5 metres.

All millimetre conversions