Millimeters to Micrometers
Convert millimeters to micrometers instantly. 1 mm = 1000 µm. Includes the exact factor, a conversion table of common values and the definition of both units.
How to convert millimeters to micrometers
To convert millimeters to micrometers, multiply by 1000. The relationship is fixed, so the same factor works for any quantity — there is nothing to look up and nothing that changes with temperature, location or context.
µm = mm × 1000
Millimeters to Micrometers conversion table
The values people look up most often, rounded for reading. Use the calculator above for anything in between.
| Millimeters | Micrometers |
|---|---|
| 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 |
| 500 mm | 500,000 µm |
| 1,000 mm | 1,000,000 µm |
What is a millimeter?
A thousandth of a metre. The default fine unit on metric engineering drawings.
What is a micrometer?
A millionth of a metre, also called a micron. Human hair is roughly 70 µm across.
The formula
µm = mm × 1000
Every result on this page comes from this formula. Nothing is rounded until the final display, so figures match a spreadsheet to the cent.
How to use the Millimeters to Micrometers
- Type the number of millimeters you want to convert.
- Read the result in micrometers straight away — there is no button to press.
- Check the table below for the values that come up most often, or reverse the conversion with the linked micrometers to millimeters page.
Millimeters to Micrometers — frequently asked questions
How many micrometers are in a millimeter?
One millimeter equals 1000 µm. µm = mm × 1000
What is the formula to convert millimeters to micrometers?
The formula is µm = mm × 1000. It is an exact definition rather than an approximation, so the conversion never drifts no matter how large the number.
How do I convert micrometers back to millimeters?
Divide instead of multiplying: one micrometer is 0.001 mm. The reverse converter is linked in the related tools list.
Is this conversion exact?
Yes. Both units are defined against the same base unit by international agreement, so the factor is exact — any rounding you see is only in the display, which you can widen by entering more decimal places.
Is this millimeters to micrometers free to use?
Yes. Every calculator on the site is free, needs no sign-up, and runs entirely in your browser, so your figures never leave your device.
What people search for
This page answers each of these searches. They are the exact phrases visitors use to find the millimeters to micrometers.
- millimeters to micrometers
- how many micrometers in a millimeter
- mm2µm
- millimeters in micrometers
- millimeters to micrometers converter
- convert millimeters to micrometers
- millimetres to micrometers
- mm to micrometers
About this calculator
Written and reviewed by The Samsung Calculator editorial team. Every calculator is written against a published formula, reviewed against at least one independent reference implementation, and dated when it changes.
Last reviewed August 15, 2026 · Calculation runs client-side · No data collected · Report an error