3 mm to cm — 3 millimetres in centimetres
Exact 3 ÷ 10 = 0.3
3 millimetres in other units
| Nanometres | 3,000,000 | nm |
|---|---|---|
| Micrometres | 3,000 | µm |
| Centimetres | 0.3 | cm |
| Metres | 0.003 | m |
| Kilometres | 0.000003 | km |
| Inches | 0.11811024 | in |
| Feet | 0.009842519685 | ft |
| Yards | 0.003280839895 | yd |
| Miles | 0.000001864114 | mi |
| Nautical miles | 0.00000161987 | nmi |
mm to cm at a glance
| Millimetres | Centimetres |
|---|---|
| 1 mm | 0.1 cm |
| 2 mm | 0.2 cm |
| 3 mm | 0.3 cm |
| 5 mm | 0.5 cm |
| 10 mm | 1 cm |
| 20 mm | 2 cm |
| 25 mm | 2.5 cm |
| 50 mm | 5 cm |
| 100 mm | 10 cm |
| 250 mm | 25 cm |
| 500 mm | 50 cm |
| 1,000 mm | 100 cm |
How to convert millimetres to centimetres
Multiply by 0.1 — one millimetre is 0.1 centimetres. That factor is exact: it comes from the definition of the units rather than from a measurement, so it will not change and does not need rounding.
Working 3 ÷ 10 = 0.3
What these units are
The millimetre and the centimetre are covered in the length unit guide, along with every other unit on this page.
Questions
How many centimetres are in a millimetre?
One millimetre is 0.1 centimetres. This figure is exact — it comes from the definition of the unit, not a measurement.
What is 3 millimetres in centimetres?
3 millimetres is 0.3 centimetres. The working is 3 ÷ 10 = 0.3.
Is an inch exactly 2.54 centimetres?
Yes, exactly. Since 1959 the international inch has been defined as 25.4 millimetres, so the figure is a definition rather than a measurement. Every foot, yard and mile figure on this page follows from it and is equally exact.
Why is a nautical mile different from a mile?
It is tied to the Earth rather than to a body part. One nautical mile is one minute of latitude, fixed at exactly 1,852 metres, which makes chart work straightforward for anyone navigating by degrees.
How do I write my height in metric?
Convert the whole thing to inches first, then multiply by 2.54. Five foot ten is 70 inches, which is 177.8 cm. Converting the feet and the inches separately is where the arithmetic usually goes wrong.
Meter or metre?
Both name the same unit. "Metre" is the international spelling used by the SI and most English-speaking countries; "meter" is standard in the United States. Either spelling will find this page.