mm
What is a millimeter?
Used in precision engineering, manufacturing and rainfall reports
Definition
The millimeter equals one thousandth of a meter and is essential in precision engineering, manufacturing and rainfall measurement. A 10-millimetre rainfall is a moderate shower; over 50 mm in a day is classified as heavy. Machined parts, screws and PCB dimensions are all given in mm.
Common uses
- Rainfall measurements in weather reports
- Precision engineering and manufacturing tolerances
- Medical imaging — tumor and wound size
🌍 Real-world scale
A 2 euro coin is 25.75 mm across and 2.2 mm thick. Rainfall of 50 mm in 24 h is a red-warning event in most of Europe.
Convert from millimeters
14 conversionsMillimeter to Meter1 mm = 0.001 mMillimeter to Kilometer1 mm = 1.0000e-6 kmMillimeter to Centimeter1 mm = 0.1 cmMillimeter to Mile1 mm = 6.2137e-7 miMillimeter to Yard1 mm = 0.001094 ydMillimeter to Foot1 mm = 0.003281 ftMillimeter to Inch1 mm = 0.03937 inMillimeter to Nautical Mile1 mm = 5.3996e-7 nmiMillimeter to Micrometer1 mm = 1,000 µmMillimeter to Nanometer1 mm = 1,000,000 nmMillimeter to Light Year1 mm = 1.0570e-19 lyMillimeter to Furlong1 mm = 4.9710e-6 furMillimeter to Fathom1 mm = 0.0005468 ftmMillimeter to Angstrom1 mm = 10,000,000 Å
Convert to millimeters
14 conversionsMeter to Millimeter1 m = 1,000 mmKilometer to Millimeter1 km = 1,000,000 mmCentimeter to Millimeter1 cm = 10 mmMile to Millimeter1 mi = 1,609,344 mmYard to Millimeter1 yd = 914.4 mmFoot to Millimeter1 ft = 304.8 mmInch to Millimeter1 in = 25.4 mmNautical Mile to Millimeter1 nmi = 1,852,000 mmMicrometer to Millimeter1 µm = 0.001 mmNanometer to Millimeter1 nm = 1.0000e-6 mmLight Year to Millimeter1 ly = 9.4607e18 mmFurlong to Millimeter1 fur = 201,168 mmFathom to Millimeter1 ftm = 1,828.8 mmAngstrom to Millimeter1 Å = 1.0000e-7 mm
Tips
- 1 mm is the smallest graduation on a standard ruler. 10 mm = 1 cm exactly.
- Rainfall in mm is depth — 25 mm of rain over 1 m² equals 25 litres of water.
- For very small measurements switch to micrometres (µm) — 1 mm = 1000 µm.
Common mistakes
- Reading an engineering drawing dimensioned in mm as if it were cm — a factor-of-10 error.
- Using 25 instead of 25.4 when converting mm to inches — the error matters in CNC machining.
- Confusing millimetre (length) with millilitre (volume) — both abbreviated with "ml" but on different scales.
FAQ about the millimeter
Explore all 15 length units and their conversions.📏 Length hub →