Centimeters to millimeters converter
Convertersconversion pair
Convert centimeters to millimeters instantly: 1 cm is 10 mm. Rulers, plans and small parts, with the exact math and one-click copying.
multiply by 10 — the metric conversion that still can't be got wrong.
work surface
Math, not advice — results are indicative. Read the disclaimer.
pro tips
Multiply by 10: 7.5 cm becomes 75 mm with a single added zero.
1 cm is 10 mm, and 100 cm is 1,000 mm — a metre in disguise.
Watch and jewellery specs love mm; the wrists they measure often live in cm.
what it does
Going from centimeters to millimeters is the metric system showing off: multiply by 10 and you're finished. One centimeter is ten millimeters, in every country that ever signed a treaty or bought a ruler.
You meet it when a drawing is dimensioned in cm but the cut has to be in mm — cabinetry, plumbing, sewing patterns, model kits — and when a doctor or a delivery app reports "2.5 cm" while something downstream needs "25 mm" for the machine to understand.
The shortcut is free: add a zero. 3 cm is 30 mm, 7.5 cm is 75 mm, and 100 cm is 1,000 mm, which is one metre politely reintroducing itself. There is no decimal to carry and no fraction to forgive.
Type any centimeter value and the widget answers in millimeters instantly, with the math on screen. Click to copy, and hit swap when the plan flips and someone hands you millimeters to shrink back down.
quick answers
How many millimeters are in a centimeter?
10 exactly. It's the metric system's least controversial fact.
Is 2.5 cm the same as 25 mm?
Yes. Move the decimal one place and the units swap labels.
Why do plans use cm but cuts use mm?
Humans sketch in centimeters; machines, and the mistakes feeding them, prefer millimeters.