How this calculator works
The SI prefix milli means one thousandth. A millimetre is therefore exactly 0.001 metre. Divide by 1000 to read a component or construction drawing in metres; multiply by 1000 when a metre-based model needs dimensions in millimetres.
Formula
m = mm / 1000; mm = m x 1000.
Worked example
A 2450 mm board is 2.45 m long. A 0.075 m spacer measures 75 mm.
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Frequently asked questions
How many millimetres make a metre?
Exactly 1000.
Is 1 mm the same as 0.01 m?
No. One millimetre is 0.001 m; 0.01 m is one centimetre.
Can I enter a decimal millimetre?
Yes. For example, 0.25 mm is 0.00025 m.