Convert Thou to Meters
1 thou is 0.0000254 m. One thou is exactly 0.0000254 meters.
One thou is 2.5400 × 10^-5 meters. To convert thou to meters, multiply by 2.5400 × 10^-5; to go the other way, divide by 2.5400 × 10^-5 or multiply by 39370.079. The relation is exact but the figure is not: it is a rounding of a number that does not terminate, and it follows from NIST.
Factor checked against the defining standard · How we check
- Thou × 2.5400 × 10^-5
1 * 0.00002540 m
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 metres 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 meters? The converter and the working
- 1.Take the measurement in thou.
- 2.Multiply by 2.5400 × 10^-5 — that is how many meters fit in one thou.
- 3.To go back the other way, divide by 2.5400 × 10^-5, or multiply by 39370.079.
Worked example: 25 thou to meters
- Formula
- thou × 2.5400 × 10^-5 = m
- Arithmetic
- 25 × 2.5400 × 10^-5 = 0.000635 m
- Answer
- 25 thou = 0.000635 m
The factor is rounded for display; the figure above is computed from the full value.
Thou to meters conversion table
| Thou | Meters |
|---|---|
| 1 thou | 0.0000254 m |
| 2 thou | 0.0000508 m |
| 3 thou | 0.0000762 m |
| 4 thou | 0.0001016 m |
| 5 thou | 0.000127 m |
| 6 thou | 0.0001524 m |
| 7 thou | 0.0001778 m |
| 8 thou | 0.0002032 m |
| 9 thou | 0.0002286 m |
| 10 thou | 0.000254 m |
| 12 thou | 0.0003048 m |
| 15 thou | 0.000381 m |
| 20 thou | 0.000508 m |
| 25 thou | 0.000635 m |
| 50 thou | 0.00127 m |
| 100 thou | 0.00254 m |
| 200 thou | 0.01 m |
| 300 thou | 0.01 m |
| 500 thou | 0.01 m |
| 1000 thou | 0.03 m |
| 2000 thou | 0.05 m |
| 5000 thou | 0.13 m |
| 10000 thou | 0.25 m |
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 meter?
The SI base unit, defined since 1983 by the distance light travels in 1/299,792,458 of a second.
How many meters are in a thou?
One thou is 2.5400 × 10^-5 meters. Going the other way, one meter is 39370.079 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 meters. Rule Calculator. https://rulecalculators.com/convert/thou-to-meter
- MLA
- "Convert Thou to meters." Rule Calculator, August 16, 2026, https://rulecalculators.com/convert/thou-to-meter.
- Chicago
- Rule Calculator. "Convert Thou to meters." Rule Calculator. Last reviewed August 16, 2026. https://rulecalculators.com/convert/thou-to-meter.
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 meters are in a thou?
- 2.5400 × 10^-5. The SI base unit, defined since 1983 by the distance light travels in 1/299,792,458 of a second.
- How do I convert meters back to thou?
- Divide by 2.5400 × 10^-5, or multiply by 39370.079 — they are the same operation.
Other length conversions
Meters to thou — the same conversion the other way.