Convert millimetres to centimetres

One millimetre is 0.1 centimetres. To convert any amount, multiply by 0.1. Going the other way, one centimetre is 10 millimetres.

Multiply the millimetre figure by 0.1. So cm = mm × 0.1. For a quick mental estimate, dividing by about 10 gets you close enough for most everyday purposes.

One millimetre is roughly the thickness of a credit card, which is 0.76 mm. The millimetre is the working unit of engineering drawings and machining tolerances almost everywhere metric is used, because it avoids decimals for most part dimensions.

One centimetre is about the width of an adult fingernail. The centimetre is the everyday metric unit for body measurements and paper sizes, though it is not an SI-preferred prefix step — engineers tend to jump from millimetres to metres.

Yes. Since the 1959 international yard and pound agreement, the imperial and metric systems are related by exact definitions rather than measurements — the inch is exactly 25.4 mm and the pound exactly 0.45359237 kg. Everything derived from those, including this conversion, is therefore exact. Round at the end rather than partway through, since rounding mm before converting introduces an error the conversion then multiplies.