Mils to Micrometers
Convert mils to micrometers instantly. 1 mil = 25.4 µm. Includes the exact factor, a conversion table of common values and the definition of both units.
How to convert mils to micrometers
To convert mils to micrometers, multiply by 25.4. 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 = mil × 25.4
Mils to Micrometers conversion table
The values people look up most often, rounded for reading. Use the calculator above for anything in between.
| Mils | Micrometers |
|---|---|
| 1 mil | 25.4 µm |
| 2 mil | 50.8 µm |
| 3 mil | 76.2 µm |
| 5 mil | 127 µm |
| 10 mil | 254 µm |
| 20 mil | 508 µm |
| 25 mil | 635 µm |
| 50 mil | 1,270 µm |
| 100 mil | 2,540 µm |
| 500 mil | 12,700 µm |
| 1,000 mil | 25,400 µm |
What is a mil?
One thousandth of an inch. Standard for PCB traces, foil and coating thickness.
What is a micrometer?
A millionth of a metre, also called a micron. Human hair is roughly 70 µm across.
The formula
µm = mil × 25.4
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 Mils to Micrometers
- Type the number of mils 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 mils page.
Mils to Micrometers — frequently asked questions
How many micrometers are in a mil?
One mil equals 25.4 µm. µm = mil × 25.4
What is the formula to convert mils to micrometers?
The formula is µm = mil × 25.4. 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 mils?
Divide instead of multiplying: one micrometer is 0.0393700787 mil. 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 mils 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 mils to micrometers.
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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