Aisha K.
Mar 12, 2026
Clean layout and the results update instantly. Exactly what I needed for a quick planning check.
Unit Converters
Horsepower to Watts Converter (hp to W)
watts = mechanical hp × 745.69987. kilowatts = hp × 0.7457.
Mechanical horsepower is 745.7 W. A 150 hp engine is 112 kW. Metric PS is 735.5 W — close, not the same. Peak dyno hp is not what the wheels see. Convert the number on the spec sheet, then stay humble.
Mechanical horsepower
hp → W
745.7 W
1 hp → 746 W. 400 hp → 298 kW.
- You typed
- 1 hp
- One W is
- 0 hp
- How it’s calculated
- watts = mechanical hp × 745.69987. kilowatts = hp × 0.7457.
Plain-English guide
Terms & how it works
Confused by a field? Read the short definitions here while you use the tool.
Mechanical horsepower
The “Mechanical horsepower” value used in this tool’s formula. Adjust it to see results update live.
How this calculator works
Mechanical horsepower is 745.7 W. A 150 hp engine is 112 kW. Metric PS is 735.5 W — close, not the same. Peak dyno hp is not what the wheels see. Convert the number on the spec sheet, then stay humble. watts = mechanical hp × 745.69987. kilowatts = hp × 0.7457. Example: 1 hp → 746 W. 400 hp → 298 kW.
watts = mechanical hp × 745.69987. kilowatts = hp × 0.7457.
Example: 1 hp → 746 W. 400 hp → 298 kW.
When to use this Horsepower to Watts
Common use cases
- Mechanical horsepower is 745.7 W. A 150 hp engine is 112 kW. Metric PS is 735.5 W — close, not the same. Peak dyno hp is not what the wheels see. Convert the number on the spec sheet, then stay humble.
- Sanity-check with this case: 1 hp → 746 W. 400 hp → 298 kW.
- The relationship is: watts = mechanical hp × 745.69987. kilowatts = hp × 0.7457.
Localized examples
- Unit Converters: the example on this page uses the same formula as the widget.
What you get
- Fields: Mechanical horsepower
- watts = mechanical hp × 745.69987. kilowatts = hp × 0.7457.
- Example on the page: 1 hp → 746 W. 400 hp → 298 kW.
How to Convert Horsepower to Watts Step-by-Step
- 1Enter Mechanical horsepower. Use the values you have, not a catalog average, unless that is all you know.
- 2watts = mechanical hp × 745.69987. kilowatts = hp × 0.7457.
- 3Worked case: 1 hp → 746 W. 400 hp → 298 kW.
- 4Check which dictionary the other person is using — US or UK, decimal or 1,024 — then trust the number.
Governing formula
watts = mechanical hp × 745.69987. kilowatts = hp × 0.7457.
1 hp → 746 W. 400 hp → 298 kW.
Example: set Mechanical horsepower = 1, then read the result.
Variable definitions
- value
Mechanical horsepower
The “Mechanical horsepower” field. Default 1; typical range 0–10000.
- The conversion (watts = mechanical hp × 745.69987. kilowatts = hp × 0.7457.) does not pick US vs UK gallons, SI vs binary megabytes, or Mach at altitude for you. Read the footnote on the page.
- Nothing here is uploaded for the calculation itself.
Frequently Asked Questions
Often rated in kW already. 100 kW is 134 hp.
Related calculators
Unit Converters
- Kilowatts to HorsepowerDivide kW by 0.7457 (or multiply by 1.341). A 100 kW electric motor is 134 hp. EV brochures already did this; ICE dyno sheets sometimes did not. Metric PS is 1.36 hp per kW — close enough to start a fight.
- Appliance Running CostCost = watts × hours / 1000 × $/kWh. A 1,500 W space heater for 4 hours at $0.16/kWh is $0.96. The supply rate on the bill is the one that matters, not a national average.
- dBm to WattsP(W) = 10^((dBm − 30)/10). 0 dBm is 1 mW. 30 dBm is 1 W. Wi-Fi EIRP limits are a regulator’s problem; this is just the log.
- Decibels to W/m²I = 10⁻¹² × 10^(L/10) W/m². 0 dB SPL is the quiet threshold, 60 dB a chat, 120 dB a pain rumor. Loudness is not intensity; +10 dB is 10× intensity and roughly twice as loud to a human ear.
- SI Watt Prefix ConverterPhone chargers in watts, homes in kilowatts, plants in megawatts, grids in gigawatts. A 1.5 kW kettle is 1,500 W. Terawatts show up in climate-scale diagrams, not in a breaker panel.
- Solar Panel Daily kWhkWh/day ≈ (array W / 1000) × peak sun hours. A 400 W panel in 4.5 PSH is 1.8 kWh before dirt, heat, and inverter loss (often 0.75–0.85). NREL sun-hour maps beat a guess.
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4.8
out of 5.0
4 reviews
Daniel R.
Feb 28, 2026
Very usable on mobile. Would love a save/export option later, but the math feels solid.
Priya S.
Feb 3, 2026
The FAQ section answered my questions before I even had to search. Smooth dark mode too.
Marcus L.
Jan 19, 2026
Simple inputs, clear outputs. This replaced three bookmarks I used to juggle.
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