Watts to Kilowatts Converter
Quick explanation
Convert between watts and kilowatts using the formula kW = W ÷ 1000 (or W = kW × 1000). Type in either field and the other updates live. Watts appear on appliance nameplates and energy monitors; kilowatts appear on utility bills and generator specs. For the next step, try the kWh calculator to estimate energy use over time, or the electricity cost calculator to put a dollar figure on it. For broader formula checks, see the Ohm's Law calculator.
1000 W = 1 kW
Watts and kilowatts: what is the difference?
Watts and kilowatts measure the same thing, power, just at different scales. One kilowatt is exactly 1000 watts. The "kilo" prefix simply means 1000, the same as in kilometer or kilogram.
Appliance labels use watts because individual devices are in the hundreds-of-watts range. A 60 W light bulb, a 1500 W heater, an 1100 W microwave. But utility bills and generator specs use kilowatts because they describe loads at the household or grid scale, where "1.5 kW" is easier to read than "1500 W".
Knowing the kW equivalent of your appliances is useful when reading your electricity bill, comparing generator capacity, or estimating daily kWh consumption. The math is always the same: divide by 1000 to go from watts to kilowatts, and multiply by 1000 to go the other way.
How to convert
Watts to kilowatts
Divide wattage by 1000 to get kilowatts.
kW = W ÷ 1000
kilowatts = watts ÷ 1000
Kilowatts to watts
Multiply kilowatts by 1000 to get watts.
W = kW × 1000
watts = kilowatts × 1000
Worked examples
Question: A space heater is rated 1500 W. What is that in kW?
Solution: kW = 1500 ÷ 1000 = 1.5 kW
Question: A portable generator is rated 3.5 kW. How many watts is that?
Solution: W = 3.5 × 1000 = 3500 W
Question: A home draws an average of 1.2 kW. How many watts is that?
Solution: W = 1.2 × 1000 = 1200 W
Common mistakes and notes
- The conversion is exact: 1 kW = 1000 W, no rounding required.
- kW is a unit of power (rate of energy use). kWh is a unit of energy (power × time). They are different quantities.
- Appliance nameplates show rated watts, which is peak draw. Actual average draw can be lower for devices that cycle (refrigerators, thermostats, etc.).
- Generator capacity is typically given in kW or kVA. If rated in kVA, multiply by the power factor to get kW.
Assumptions
- The conversion is exact: 1 kW = 1000 W by definition.
- Input wattage is the steady-state draw. Startup surges and cycling behavior are not modeled.
- Use nameplate or measured wattage for accuracy; rated wattage can differ from actual draw.
Worked example
Example: A 1500 W space heater is 1500 ÷ 1000 = 1.5 kW. Running it for 4 hours uses 6 kWh.
FAQ
How do you convert watts to kilowatts?
Divide watts by 1000: kW = W ÷ 1000. For example, a 1500 W space heater is 1.5 kW.
How do you convert kilowatts to watts?
Multiply kilowatts by 1000: W = kW × 1000. For example, a 3.5 kW air conditioner is 3500 W.
Why does my utility bill use kW and kWh instead of watts?
Kilowatts are a more convenient scale for household and grid-level loads. Watts are fine for labeling individual appliances, but a typical home draws several thousand watts at once, which is easier to express as a few kilowatts. kWh (kilowatt-hours) is the unit your meter counts over time: 1 kWh = 1 kW running for 1 hour.
Is 1000 watts exactly 1 kilowatt?
Yes. The prefix "kilo" means 1000 in SI units, so the conversion is exact by definition, not an approximation.
What is the difference between kW and kWh?
kW is power, the rate of energy use at a given instant. kWh is energy, the total amount used over time. A 2 kW device running for 3 hours uses 6 kWh. Your utility charges for kWh, not kW.
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⚠️ Sanity Check Only
This tool provides informational estimates only. It is not professional engineering advice. Electrical work is dangerous and governed by strict local codes.
Before you start:
- Verify these results with a licensed electrician.
- Cross-reference with the latest Electrical Code (NEC/CEC).
- Never work on live circuits.