Power
Power is energy per time – 1 W = 1 J/s. The metric horsepower is exactly 735.49875 W. Edit, print and share.
The power table: 1 megawatt = 1 000 kilowatts, 1 kilowatt = 1 000 watts, 1 watt = 1 000 milliwatts – plus the metric horsepower, exactly 735.49875 W. Made for the classroom and home.
| 1 MW | = | 1 000 kW |
|---|---|---|
| 1 kW | = | 1 000 W |
| 1 W | = | 1 000 mW |
| 1 MW | = | 1 000 000 W |
| 1 kW | = | 1 000 000 mW |
| 1 hp (metric) | = | 735.49875 W |
| 1 hp (metric) | = | 0.73549875 kW |
| 1 W | = | 0.001 kW |
How the table works
Every row is a unit conversion: a quantity and unit on the left, the same quantity expressed in another unit on the right. The table is live – drag the handle to reorder, click a row to change the quantity or units, remove rows with the cross and add your own at the bottom.
Everything you change lands in the page address. Copy the link and others open exactly your table – handy when the whole class needs the same sheet. Your changes are also kept in your browser until you reset them, but only there: to share or keep them permanently, the link is what counts.
Print puts the table on a single portrait A4 and Download PDF gives you the same sheet as a file. Print practice sheet gives the table with empty answer cells and name/date lines – the normal printout is the answer key.
Power is energy per time
Power measures how fast energy is used or produced: one watt is exactly one joule per second (1 W = 1 J/s). The higher the power, the faster the energy flows.
Good to know: horsepower (hp) is an older unit that survives for cars and engines. The metric horsepower is exactly 735.49875 W – an odd-looking number that comes from its historical definition (75 kilogram-force-metres per second). The mechanical (imperial) horsepower is a different unit, about 745.7 W, whose exact value needs too many decimals for this table’s exact-value rule – the table carries the metric horsepower only.
Roughly how much power?
- A phone charger uses roughly 20 W.
- A microwave oven uses roughly 800 W.
- An electric heater uses roughly 1 kW.
- A small car has roughly 100 hp (roughly 74 kW).
Frequently asked questions
How many watts are there in a horsepower?
735.49875 W exactly (metric horsepower).
How do I convert kW to hp?
1 kW is roughly 1.36 hp – an approximate figure in that direction. The table shows the exact direction, hp to kW and W.
What does watt measure?
Energy per second – how fast energy is used or produced.
More tables: Energy · Time · Prefix ladder · Power converter