Convert Inches to Micrometers
1 inch is 25,400 µm. One inch is exactly 25400 micrometers.
One inch is 25400 micrometers. To convert inches to micrometers, multiply by 25400; to go the other way, divide by 25400 or multiply by 3.9370 × 10^-5. The factor is exact rather than rounded: it follows from NIST. Exactly 25.4 millimeters since the 1959 international yard and pound agreement, and one twelfth of a foot.
Factor checked against the defining standard · How we check
- Inches × 25400
1 * 2540025,400 µm
1 inch in every length unit
| Unit | Value | Exact factor |
|---|---|---|
| inches (as entered) | 1 in | — |
| feet | 0.08333333333 ft | × 0.0833333333333 |
| yards | 0.02777777778 yd | × 0.0277777777778 |
| miles | 0.00001578282828 mi | × 0.0000157828282828 |
| millimeters | 25.4 mm | × 25.4 |
| decimetres | 0.254 dm | × 0.254 |
| centimeters | 2.54 cm | × 2.54 |
| meters | 0.0254 m | × 0.0254 |
| kilometers | 0.0000254 km | × 0.0000254 |
| nautical miles | 0.00001371490281 nmi | × 0.0000137149028078 |
| micrometers | 25,400 µm | × 25,400 |
| nanometers | 25,400,000 nm | × 25,400,000 |
| thou | 1,000 thou | × 1,000 |
Factors are entered by hand from NIST rather than derived from a units library, so the ones that terminate are exact rather than rounded.
The same converter answers this pair however it is written: inches to micrometres is the British spelling of the same units — the metre and the litre are spelled that way outside the United States and the quantity does not change.
How do you convert inches to micrometers? The converter and the working
- 1.Take the measurement in inches.
- 2.Multiply by 25400 — that is how many micrometers fit in one inch.
- 3.To go back the other way, divide by 25400, or multiply by 3.9370 × 10^-5.
Worked example: 25 inches to micrometers
- Formula
- in × 25400 = µm
- Arithmetic
- 25 × 25400 = 635,000 µm
- Answer
- 25 in = 635,000 µm
The factor is exact, so this figure is exact too — only the display is rounded.
Inches to micrometers conversion table
| Inches | Micrometers |
|---|---|
| 1 in | 25,400 µm |
| 2 in | 50,800 µm |
| 3 in | 76,200 µm |
| 4 in | 101,600 µm |
| 5 in | 127,000 µm |
| 6 in | 152,400 µm |
| 7 in | 177,800 µm |
| 8 in | 203,200 µm |
| 9 in | 228,600 µm |
| 10 in | 254,000 µm |
| 12 in | 304,800 µm |
| 15 in | 381,000 µm |
| 20 in | 508,000 µm |
| 25 in | 635,000 µm |
| 50 in | 1,270,000 µm |
| 100 in | 2,540,000 µm |
| 200 in | 5,080,000 µm |
| 300 in | 7,620,000 µm |
| 500 in | 12,700,000 µm |
| 1000 in | 25,400,000 µm |
| 2000 in | 50,800,000 µm |
| 5000 in | 127,000,000 µm |
| 10000 in | 254,000,000 µm |
What is an inch?
Exactly 25.4 millimeters since the 1959 international yard and pound agreement, and one twelfth of a foot.
What is a micrometer?
A millionth of a meter, still widely called a micron. Machining tolerances, filter ratings and cell diameters are all quoted here.
How many micrometers are in an inch?
One inch is 25400 micrometers, exactly. Going the other way, one micrometer is 3.9370 × 10^-5 inches. Both figures come from the same defined relation rather than from a measurement, which is why they are the same today as they were in 1959.
Every length unit here
The whole group — 13 units with their symbols and the size of each one in meters — is on the conversion index, along with every pair it makes. The table above already gives each of them relative to an inch.
Source: NIST — international yard and pound agreement (inch = 25.4 mm exactly)
Cite this page
- APA
- Rule Calculator. (2026). Convert Inches to micrometers. Rule Calculator. https://rulecalculators.com/convert/inch-to-micrometer
- MLA
- "Convert Inches to micrometers." Rule Calculator, August 16, 2026, https://rulecalculators.com/convert/inch-to-micrometer.
- Chicago
- Rule Calculator. "Convert Inches to micrometers." Rule Calculator. Last reviewed August 16, 2026. https://rulecalculators.com/convert/inch-to-micrometer.
The date is when the figures on this page were last checked against their source, not the day you opened it. Add your own access date if your style needs one.
Questions people actually ask
- How many micrometers are in an inch?
- 25400. A millionth of a meter, still widely called a micron. Machining tolerances, filter ratings and cell diameters are all quoted here.
- How do I convert micrometers back to inches?
- Divide by 25400, or multiply by 3.9370 × 10^-5 — they are the same operation.
Other length conversions
Micrometers to inches — the same conversion the other way.