Convert Thou to Decimetres
1 thou is 0.000254 dm. One thou is exactly 0.000254 decimetres.
One thou is 2.5400 × 10^-4 decimetres. To convert thou to decimetres, multiply by 2.5400 × 10^-4; to go the other way, divide by 2.5400 × 10^-4 or multiply by 3937.0079. 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^-4
1 * 0.0002540 dm
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.
How do you convert thou to decimetres? The converter and the working
- 1.Take the measurement in thou.
- 2.Multiply by 2.5400 × 10^-4 — that is how many decimetres fit in one thou.
- 3.To go back the other way, divide by 2.5400 × 10^-4, or multiply by 3937.0079.
Worked example: 25 thou to decimetres
- Formula
- thou × 2.5400 × 10^-4 = dm
- Arithmetic
- 25 × 2.5400 × 10^-4 = 0.01 dm
- Answer
- 25 thou = 0.01 dm
The factor is rounded for display; the figure above is computed from the full value.
Thou to decimetres conversion table
| Thou | Decimetres |
|---|---|
| 1 thou | 0.000254 dm |
| 2 thou | 0.000508 dm |
| 3 thou | 0.000762 dm |
| 4 thou | 0.001016 dm |
| 5 thou | 0.00127 dm |
| 6 thou | 0.001524 dm |
| 7 thou | 0.001778 dm |
| 8 thou | 0.002032 dm |
| 9 thou | 0.002286 dm |
| 10 thou | 0.00254 dm |
| 12 thou | 0.003048 dm |
| 15 thou | 0.00381 dm |
| 20 thou | 0.01 dm |
| 25 thou | 0.01 dm |
| 50 thou | 0.01 dm |
| 100 thou | 0.03 dm |
| 200 thou | 0.05 dm |
| 300 thou | 0.08 dm |
| 500 thou | 0.13 dm |
| 1000 thou | 0.25 dm |
| 2000 thou | 0.51 dm |
| 5000 thou | 1.27 dm |
| 10000 thou | 2.54 dm |
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 decimetre?
A tenth of a metre. Rare in speech and unavoidable in definitions: the litre is a cubic decimetre, which is where the millilitre and the cubic centimetre meet.
How many decimetres are in a thou?
One thou is 2.5400 × 10^-4 decimetres. Going the other way, one decimetre is 3937.0079 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 decimetres. Rule Calculator. https://rulecalculators.com/convert/thou-to-decimeter
- MLA
- "Convert Thou to decimetres." Rule Calculator, August 16, 2026, https://rulecalculators.com/convert/thou-to-decimeter.
- Chicago
- Rule Calculator. "Convert Thou to decimetres." Rule Calculator. Last reviewed August 16, 2026. https://rulecalculators.com/convert/thou-to-decimeter.
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Questions people actually ask
- How many decimetres are in a thou?
- 2.5400 × 10^-4. A tenth of a metre. Rare in speech and unavoidable in definitions: the litre is a cubic decimetre, which is where the millilitre and the cubic centimetre meet.
- How do I convert decimetres back to thou?
- Divide by 2.5400 × 10^-4, or multiply by 3937.0079 — they are the same operation.
Other length conversions
Decimetres to thou — the same conversion the other way.