Convert Milliwatts to Horsepower
1 milliwatt is 0.000001341 hp. One milliwatt is exactly 0.0000013410220896 horsepower.
One milliwatt is 1.3410 × 10^-6 horsepower. To convert milliwatts to horsepower, multiply by 1.3410 × 10^-6; to go the other way, divide by 1.3410 × 10^-6 or multiply by 745699.87. 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 Special Publication 811. A thousandth of a watt.
Factor checked against the defining standard · How we check
- Milliwatts × 1.3410 × 10^-6
1 * 0.00000130 hp
1 milliwatt in every power unit
| Unit | Value | Exact factor |
|---|---|---|
| horsepower | 0.00000134102209 hp | × 0.0000013410220896 |
| metric horsepower | 0.000001359621617 PS | × 0.0000013596216173 |
| watts | 0.001 W | × 0.001 |
| kilowatts | 0.000001 kW | × 0.000001 |
| milliwatts (as entered) | 1 mW | — |
| megawatts | 0.000000001 MW | × 0.000000001 |
| tons of refrigeration | 0.0000002843451361 TR | × 0.000000284345136094 |
| BTU per hour | 0.003412141633 BTU/h | × 0.00341214163313 |
Factors are entered by hand from NIST Special Publication 811 rather than derived from a units library, so the ones that terminate are exact rather than rounded.
How do you convert milliwatts to horsepower? The converter and the working
- 1.Take the measurement in milliwatts.
- 2.Multiply by 1.3410 × 10^-6 — that is how many horsepower fit in one milliwatt.
- 3.To go back the other way, divide by 1.3410 × 10^-6, or multiply by 745699.87.
Worked example: 25 milliwatts to horsepower
- Formula
- mW × 1.3410 × 10^-6 = hp
- Arithmetic
- 25 × 1.3410 × 10^-6 = 0.00003353 hp
- Answer
- 25 mW = 0.00003353 hp
The factor is rounded for display; the figure above is computed from the full value.
Milliwatts to horsepower conversion table
| Milliwatts | Horsepower |
|---|---|
| 1 mW | 0.000001341 hp |
| 2 mW | 0.000002682 hp |
| 3 mW | 0.000004023 hp |
| 4 mW | 0.000005364 hp |
| 5 mW | 0.000006705 hp |
| 6 mW | 0.000008046 hp |
| 7 mW | 0.000009387 hp |
| 8 mW | 0.00001073 hp |
| 9 mW | 0.00001207 hp |
| 10 mW | 0.00001341 hp |
| 12 mW | 0.00001609 hp |
| 15 mW | 0.00002012 hp |
| 20 mW | 0.00002682 hp |
| 25 mW | 0.00003353 hp |
| 50 mW | 0.00006705 hp |
| 100 mW | 0.0001341 hp |
| 200 mW | 0.0002682 hp |
| 300 mW | 0.0004023 hp |
| 500 mW | 0.0006705 hp |
| 1000 mW | 0.001341 hp |
| 2000 mW | 0.002682 hp |
| 5000 mW | 0.01 hp |
| 10000 mW | 0.01 hp |
What is a milliwatt?
A thousandth of a watt. Radio transmit power, laser output and audio signal levels are all quoted in it, and dBm is referenced to exactly one.
What is a horsepower?
Mechanical horsepower: exactly 550 foot-pounds of work every second, the figure James Watt settled on to sell engines against pit ponies. US vehicle and motor ratings use it.
How many horsepower are in a milliwatt?
One milliwatt is 1.3410 × 10^-6 horsepower. Going the other way, one horsepower is 745699.87 milliwatts. 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 power unit here
The whole group — 8 units with their symbols and the size of each one in watts — is on the conversion index, along with every pair it makes. The table above already gives each of them relative to a milliwatt.
Source: NIST Special Publication 811 — mechanical horsepower is 550 ft·lbf/s exactly
Cite this page
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- Rule Calculator. (2026). Convert Milliwatts to horsepower. Rule Calculator. https://rulecalculators.com/convert/milliwatt-to-horsepower
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- "Convert Milliwatts to horsepower." Rule Calculator, August 16, 2026, https://rulecalculators.com/convert/milliwatt-to-horsepower.
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- Rule Calculator. "Convert Milliwatts to horsepower." Rule Calculator. Last reviewed August 16, 2026. https://rulecalculators.com/convert/milliwatt-to-horsepower.
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Questions people actually ask
- How many horsepower are in a milliwatt?
- 1.3410 × 10^-6. Mechanical horsepower: exactly 550 foot-pounds of work every second, the figure James Watt settled on to sell engines against pit ponies. US vehicle and motor ratings use it.
- How do I convert horsepower back to milliwatts?
- Divide by 1.3410 × 10^-6, or multiply by 745699.87 — they are the same operation.
Other power conversions
Horsepower to milliwatts — the same conversion the other way.