Convert Thou to Nanometers
1 thou is 25,400 nm. One thou is exactly 25400 nanometers.
One thou is 25400 nanometers. To convert thou to nanometers, 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.
Factor checked against the defining standard · How we check
- Thou × 25400
1 * 2540025,400 nm
1 thou in every length unit
| Unit | Value | Exact factor |
|---|---|---|
| inches | 0.001 in | × 0.001 |
| feet | 0.00008333333333 ft | × 0.0000833333333333 |
| yards | 0.00002777777778 yd | × 0.0000277777777778 |
| miles | 0.00000001578282828 mi | × 0.0000000157828282828 |
| millimeters | 0.0254 mm | × 0.0254 |
| decimetres | 0.000254 dm | × 0.000254 |
| centimeters | 0.00254 cm | × 0.00254 |
| meters | 0.0000254 m | × 0.0000254 |
| kilometers | 0.0000000254 km | × 0.0000000254 |
| nautical miles | 0.00000001371490281 nmi | × 0.0000000137149028078 |
| micrometers | 25.4 µm | × 25.4 |
| nanometers | 25,400 nm | × 25,400 |
| thou (as entered) | 1 thou | — |
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: thou to nanometres 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 thou to nanometers? The converter and the working
- 1.Take the measurement in thou.
- 2.Multiply by 25400 — that is how many nanometers fit in one thou.
- 3.To go back the other way, divide by 25400, or multiply by 3.9370 × 10^-5.
Worked example: 25 thou to nanometers
- Formula
- thou × 25400 = nm
- Arithmetic
- 25 × 25400 = 635,000 nm
- Answer
- 25 thou = 635,000 nm
The factor is exact, so this figure is exact too — only the display is rounded.
Thou to nanometers conversion table
| Thou | Nanometers |
|---|---|
| 1 thou | 25,400 nm |
| 2 thou | 50,800 nm |
| 3 thou | 76,200 nm |
| 4 thou | 101,600 nm |
| 5 thou | 127,000 nm |
| 6 thou | 152,400 nm |
| 7 thou | 177,800 nm |
| 8 thou | 203,200 nm |
| 9 thou | 228,600 nm |
| 10 thou | 254,000 nm |
| 12 thou | 304,800 nm |
| 15 thou | 381,000 nm |
| 20 thou | 508,000 nm |
| 25 thou | 635,000 nm |
| 50 thou | 1,270,000 nm |
| 100 thou | 2,540,000 nm |
| 200 thou | 5,080,000 nm |
| 300 thou | 7,620,000 nm |
| 500 thou | 12,700,000 nm |
| 1000 thou | 25,400,000 nm |
| 2000 thou | 50,800,000 nm |
| 5000 thou | 127,000,000 nm |
| 10000 thou | 254,000,000 nm |
What is a thou?
A thousandth of an inch, exactly 25.4 micrometers, and called a mil in American workshops — the same word the metric world uses for a millimeter, which is why a drawing marked "5 mil" is worth checking twice.
What is a nanometer?
A billionth of a meter. Visible light runs from about 380 to 750 nm, and a semiconductor process node is named after one even though it stopped describing a physical dimension years ago.
How many nanometers are in a thou?
One thou is 25400 nanometers, exactly. Going the other way, one nanometer is 3.9370 × 10^-5 thou. 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 a thou.
Source: NIST — international yard and pound agreement (inch = 25.4 mm exactly)
Cite this page
- APA
- Rule Calculator. (2026). Convert Thou to nanometers. Rule Calculator. https://rulecalculators.com/convert/thou-to-nanometer
- MLA
- "Convert Thou to nanometers." Rule Calculator, August 16, 2026, https://rulecalculators.com/convert/thou-to-nanometer.
- Chicago
- Rule Calculator. "Convert Thou to nanometers." Rule Calculator. Last reviewed August 16, 2026. https://rulecalculators.com/convert/thou-to-nanometer.
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 nanometers are in a thou?
- 25400. A billionth of a meter. Visible light runs from about 380 to 750 nm, and a semiconductor process node is named after one even though it stopped describing a physical dimension years ago.
- How do I convert nanometers back to thou?
- Divide by 25400, or multiply by 3.9370 × 10^-5 — they are the same operation.
Other length conversions
Nanometers to thou — the same conversion the other way.