Power from work and time, force and speed, or voltage and current — with watts, kilowatts and horsepower together.
Power
—How to use this tool
Work over time, force times speed, or voltage times current — three faces of the same quantity.
Only the pair for your chosen mode matters; the others are ignored.
All three units are shown together so mechanical and electrical power compare directly.
Power sustained for one hour gives watt-hours — the unit on your electricity bill.
Formula & worked example
1,000 J in 5 s = 200 W. 50 N at 4 m/s = 200 W. 12 V × 5 A = 60 W — the same watt in all three worlds.
Limitations — read this before you rely on it
Horsepower here is mechanical horsepower (745.7 W); metric horsepower (735.5 W) differs slightly. Electrical results assume direct current or a resistive load; AC circuits with a power factor differ.
Frequently asked questions
The rate of doing work or transferring energy — one watt is one joule per second.
Watts are a rate (like speed); watt-hours are an amount (like distance). A 200 W device running for one hour uses 200 Wh.
745.7 watts for mechanical horsepower, the figure used for engines.
They describe the same idea in different domains: mechanical work, motion and electricity all transfer energy.
A negative value means energy flowing the other way (for example regenerative braking) — this calculator works with magnitudes.