Convert mm to micrometer
Convert mm to micrometer instantly. 1 mm = 1,000 µm. Formula, worked examples and a quick reference table.
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One millimeter equals 1,000 micrometers. To convert any number of millimeters to micrometers, multiply by 1,000.
The converter above works in both directions and updates as you type. Below you will find the formula, a worked example and a reference table of common values.
Length conversions come up wherever a measurement crosses a border: a height given in feet and inches on a form that wants centimetres, a running distance recorded in kilometres and compared against miles, a component specified in millimetres and ordered from a supplier working in inches. The conversions themselves are exact — the inch, foot, yard and mile have all been defined in metric terms since 1959 — so any discrepancy comes from rounding, not from the units disagreeing.
mm to micrometer formula
To go the other way, use millimeter = micrometer ÷ 1,000.
About these units
The millimetre is the working unit of engineering drawings and machining across most of the world, precise enough that dimensions rarely need decimals.
The micrometre, or micron, is a millionth of a metre. It is the scale of bacteria, fine dust and semiconductor features, and the unit particulate air-quality limits are quoted in.
Millimeter is also written millimetre, millimetres and millimeters. Micrometer is also written micrometre, micrometres, micrometers, micron, microns and um.
Sources
mm to micrometer conversion table
| Millimeter | Micrometer |
|---|---|
| 1 mm | 1,000 µm |
| 2 mm | 2,000 µm |
| 3 mm | 3,000 µm |
| 5 mm | 5,000 µm |
| 10 mm | 10,000 µm |
| 20 mm | 20,000 µm |
| 25 mm | 25,000 µm |
| 50 mm | 50,000 µm |
| 100 mm | 100,000 µm |
| 250 mm | 250,000 µm |
| 500 mm | 500,000 µm |
| 1,000 mm | 1,000,000 µm |
Frequently asked questions
How many micrometers are in a millimeter? +
There are 1,000 micrometers in one millimeter.
What is 10 mm in µm? +
10 mm equals 10,000 µm. Multiply 10 by 1,000.
How do I convert micrometer back to millimeter? +
Use millimeter = micrometer ÷ 1,000. The converter above handles both directions, or see our dedicated micrometer to mm page.
How accurate is this millimeter to micrometer conversion? +
The factor used is 1,000, carried at full double precision. Where a unit has an exact legal definition the factor is exact rather than approximate. Rounding is applied only to the displayed result, so the answer is never a calculation done on an already-rounded number.
Is there a quick way to estimate mm to µm in my head? +
Multiply by 1,000. That matches the true factor of 1,000 exactly, so no adjustment is needed for a mental estimate.