How to Convert Micrometres to Inches (µm to in)
Length conversions come up when reading overseas furniture specs, cycling the Round Island Route in kilometres while a foreign app shows miles, or checking marine distances in the Singapore Strait in nautical miles. This guide shows how to convert micrometres into inches by hand, with examples and a quick-reference table.
The conversion
To convert micrometres to inches, multiply the value by 3.937008e-05. To go the other way, divide by the same number (or multiply by 25,400). Because the factor is tiny, scientific notation keeps the numbers manageable.
Inches = micrometres × 3.937008e-05
Worked examples
- 3 µm = 0.000118 in
- 12.5 µm = 0.000492 in
- 75 µm = 0.002953 in
Micrometres to Inches table
| Micrometres | Inches |
|---|---|
| 1 µm | 3.937008e-5 in |
| 2 µm | 7.874016e-5 in |
| 5 µm | 0.000197 in |
| 10 µm | 0.000394 in |
| 20 µm | 0.000787 in |
| 25 µm | 0.000984 in |
| 50 µm | 0.001969 in |
| 100 µm | 0.003937 in |
| 250 µm | 0.009843 in |
| 500 µm | 0.019685 in |
| 1,000 µm | 0.03937 in |
Common questions
Is µm to in exact?
The factors used here are the internationally defined values where they exist; results are rounded for display only.
How do I convert back?
Use the Inches to Micrometres converter.
Mistakes to avoid
Multiplying when you should divide
Converting to a smaller unit gives a bigger number, and converting to a larger unit gives a smaller one. If your answer moves the wrong way, you have inverted the factor.
Dropping the units
A bare number without a unit is easy to misread later. Always write the unit with the result.
Rounding the factor too early
Using 3 instead of 3.28 for feet per metre introduces an error of almost 9% before you have started.
Background
Writing the units next to every number while you work is the simplest way to avoid mistakes. If the units do not cancel to leave the one you want, the calculation is set up wrongly.
A conversion table is handy for common values, but a calculator is faster and avoids interpolation errors for anything in between.
Singapore adopted the metric system in the 1970s, replacing imperial units and traditional Chinese measures in most official uses. Metric units are now standard in schools, trade and government, but older units survive in property, markets and imported goods.
For any value, use the Micrometres to Inches Converter or browse all length converters.
Run your own numbers: Micrometres to Inches Converter