Watts to kW Converter
Convert watts to kilowatts (W to kW) for appliances, solar and electric bills
1 kW = 1,000 W, so 1 W = 0.001 kW. To convert watts to kilowatts, divide the watts by 1,000, so a 1,500 W heater is 1.5 kW.
Watts to Kilowatts converter
Live- 3.4121416 BTU/h
- 0.0013410221 hp
- 1,000 mW
- 0.000001 MW
- 1.000000e-9 GW
How to convert watts to kilowatts
The watt is the SI unit of power, one joule of energy per second. The prefix kilo always means 1,000, so a kilowatt is exactly 1,000 watts and the conversion is a pure decimal shift: move the decimal point three places to the left. No rounding is involved, and the result is exact. The power converter extends the same ladder to megawatts, horsepower and BTU per hour.
The trap is not the math but the unit that comes next. Kilowatts measure how fast energy is used; kilowatt-hours measure how much. Your electric bill charges for kWh, which is kW multiplied by hours of use. Current is a third, separate quantity: turning watts into amps needs the voltage, which the watts to amps calculator handles. Wiring and circuit sizing belong to a licensed electrician working to your local electrical code.
Step by step
- Take the power in watts from the appliance label or spec sheet.
- Divide it by 1,000 (move the decimal point three places left).
- Multiply by hours of use if you need kWh.
- Keep the lowercase k: kW, not KW.
See it on a scale
Worked examples
An old incandescent bulb, a space heater and a 32 A Level 2 EV charger.
60 W ÷ 1,000 = 0.06 kW
= 0.06 kW
1,500 W ÷ 1,000 = 1.5 kW
= 1.5 kW
7,680 W ÷ 1,000 = 7.68 kW
= 7.68 kW
How many kW is an EV charger?
A home EV charger delivers about 1.44 kW from a standard 120 V outlet and 7.68 kW from a 32 A, 240 V Level 2 unit, while public DC fast chargers are typically rated from 50 to 350 kW.
| Charger | Volts × amps | Power |
|---|---|---|
| Level 1 on a 15 A outlet | 120 V × 12 A = 1,440 W | 1.44 kW |
| Level 1 on a 20 A outlet | 120 V × 16 A = 1,920 W | 1.92 kW |
| Level 2 on a 40 A circuit | 240 V × 32 A = 7,680 W | 7.68 kW |
| Level 2 on a 60 A circuit | 240 V × 48 A = 11,520 W | 11.52 kW |
Charging current is held to 80% of the circuit rating because the NEC treats EV charging as a continuous load (Article 625), and SAE J1772 defines the AC Level 1 and Level 2 charging levels. Charging time is energy divided by power: adding 60 kWh at 7.68 kW takes about 7.8 hours, plus a little extra for charging losses.
To turn a breaker or charger rating in amps into watts at another voltage, use the amps to watts calculator. Installing a Level 2 circuit is a job for a licensed electrician working to your local electrical code.
How do I add up appliance watts to size a generator in kW?
Add the running watts of everything that will run at the same time, divide by 1,000 for kW, then add the extra starting watts of the largest motor, which the appliance or generator manual lists.
| Load | Running watts | Kilowatts |
|---|---|---|
| Refrigerator (running) | 150 W | 0.15 kW |
| Microwave oven | 1,200 W | 1.2 kW |
| LED TV | 100 W | 0.1 kW |
| Laptop | 65 W | 0.065 kW |
| Ten 10 W LED bulbs | 100 W | 0.1 kW |
| Total | 1,615 W | 1.615 kW |
Generators are often rated in kVA at a power factor of 0.8, so this 1.615 kW load calls for at least 1.615 ÷ 0.8 = 2.02 kVA of apparent power; the kVA section below explains why. Sizing so the running load stays below about 80% of the continuous rating leaves room for motor surges.
Never connect a portable generator to house wiring without a transfer switch. Have a licensed electrician install one to your local electrical code, so the generator cannot feed power back into the utility lines.
Watts to kW conversion chart
Common wattages from small electronics to whole-house loads, shown to three decimals of a kilowatt.
| Watts (W) | Kilowatts (kW) |
|---|---|
| 1 W | 0.001 kW |
| 5 W | 0.005 kW |
| 10 W | 0.01 kW |
| 25 W | 0.025 kW |
| 40 W | 0.04 kW |
| 50 W | 0.05 kW |
| 60 W | 0.06 kW |
| 75 W | 0.075 kW |
| 100 W | 0.1 kW |
| 150 W | 0.15 kW |
| 200 W | 0.2 kW |
| 250 W | 0.25 kW |
| 300 W | 0.3 kW |
| 400 W | 0.4 kW |
| 500 W | 0.5 kW |
| 600 W | 0.6 kW |
| 750 W | 0.75 kW |
| 800 W | 0.8 kW |
| 1,000 W | 1 kW |
| 1,200 W | 1.2 kW |
| 1,500 W | 1.5 kW |
| 1,800 W | 1.8 kW |
| 2,000 W | 2 kW |
| 2,500 W | 2.5 kW |
| 3,000 W | 3 kW |
| 3,500 W | 3.5 kW |
| 4,000 W | 4 kW |
| 5,000 W | 5 kW |
| 7,500 W | 7.5 kW |
| 10,000 W | 10 kW |
| 15,000 W | 15 kW |
| 50,000 W | 50 kW |
| 100,000 W | 100 kW |
Watts vs kilowatts: what is the difference?
Watts and kilowatts are the same SI unit at two scales; which one you use depends on the size of the thing you are rating.
| Attribute | Watts | Kilowatts |
|---|---|---|
| Symbol | W | kW |
| System | SI derived unit | SI |
| Defined as | 1 J/s | 1,000 W |
| One unit equals | 0.001 kW | 1,000 W |
| Typical things rated in it | LED bulbs, phone and laptop chargers, TVs, computers | Heaters, kettles, EV chargers, heat pumps, solar arrays, car engines |
| Matching energy unit | Watt-hour (Wh): power banks, laptop batteries, e-bike packs | Kilowatt-hour (kWh): electricity bills, EV batteries, home storage |
| Where it appears | Appliance labels, bulb packaging, power supply ratings | Utility demand charges, solar system sizes, EU vehicle registration papers |
| Common mistake | Confusing W with Wh | Writing KW, or confusing kW with kWh |
4 key differences
- A kilowatt is exactly 1,000 watts under the SI prefix kilo, so the conversion never introduces rounding.
- One kilowatt is 1,000 joules per second, so running it for an hour delivers 3,600,000 J, which is 1 kWh.
- A 120 V, 15 A outlet circuit can deliver at most 1.8 kW, which is why North American kettles stop near 1.5 kW while 230 V kettles reach about 3 kW.
- Solar panels are sold by the watt, but a whole rooftop system is quoted in kW, the sum of its panel ratings.
Typical appliance wattages in kilowatts
Ranges are typical ratings from product labels and vary by model. The kW figure also equals the kWh the appliance uses in one hour of continuous running at that power.
| Appliance | Typical watts | Kilowatts |
|---|---|---|
| LED bulb (60 W equivalent) | 8–10 W | 0.008–0.01 kW |
| Laptop charger | 45–100 W | 0.045–0.1 kW |
| LED TV, 55 in | 60–120 W | 0.06–0.12 kW |
| Refrigerator (while running) | 100–250 W | 0.1–0.25 kW |
| Microwave oven (input) | 900–1,500 W | 0.9–1.5 kW |
| Hair dryer | 1,200–1,875 W | 1.2–1.875 kW |
| Space heater | 1,500 W | 1.5 kW |
| Electric kettle (120 V / 230 V) | 1,500–3,000 W | 1.5–3 kW |
| Window air conditioner | 500–1,500 W | 0.5–1.5 kW |
| Electric clothes dryer | 1,800–5,000 W | 1.8–5 kW |
| Level 2 EV charger, 32 A at 240 V | 7,680 W | 7.68 kW |
How do you calculate kWh and cost from kW?
Energy is power multiplied by time: kWh = kW × hours. A 1,500 W space heater is 1.5 kW, so four hours of use is 1.5 × 4 = 6 kWh. At an example rate of 17 cents per kWh, that costs 6 × $0.17 = $1.02. Use the rate printed on your own bill, which may vary by time of day. If you timed the use in minutes, the minutes to hours converter gives the hours to multiply by.
Devices that run all day add up. A 100 W load left on 24 hours a day uses 2.4 kWh a day, or about 876 kWh a year. A 5 W standby draw uses 43.8 kWh a year.
Heat output
Electric heaters turn every watt into heat, so a 1.5 kW heater gives 1.5 kWh of heat per hour. The kWh to BTU converter shows that as 5,118 BTU, the unit US heating equipment uses.
Solar panels: watts to system kW
Home solar systems are sized in kW DC, the sum of the panel wattages. This table assumes 400 W panels and shows a rough daily output at four peak sun hours; actual output depends on location, orientation, shading and season.
| Number of 400 W panels | Total watts | System size | Energy on a 4-sun-hour day |
|---|---|---|---|
| 6 panels | 2,400 W | 2.4 kW | 9.6 kWh |
| 10 panels | 4,000 W | 4 kW | 16 kWh |
| 12 panels | 4,800 W | 4.8 kW | 19.2 kWh |
| 15 panels | 6,000 W | 6 kW | 24 kWh |
| 20 panels | 8,000 W | 8 kW | 32 kWh |
| 25 panels | 10,000 W | 10 kW | 40 kWh |
| 30 panels | 12,000 W | 12 kW | 48 kWh |
kW vs kVA: real and apparent power
Generators, UPS units and transformers are often rated in kVA (kilovolt-amperes), not kW. For AC loads with motors or electronics, current and voltage are not perfectly in step, and the power factor (PF) describes how much of the apparent power does real work: kW = kVA × PF.
Generator ratings commonly assume a power factor of 0.8, so a 10 kVA generator supplies about 8 kW of real power. Purely resistive loads such as heaters and incandescent bulbs have a power factor of 1, where watts and volt-amperes are equal. Connecting a generator or sizing its circuit must follow your local electrical code and is a job for a licensed electrician.
The metric power ladder and common slips
Every step up the ladder is a factor of 1,000: 1,000 mW = 1 W, 1,000 W = 1 kW, 1,000 kW = 1 MW and 1,000 MW = 1 GW. A phone charger is a few watts, a house draws a few kilowatts, a wind turbine produces a few megawatts and a large power station a gigawatt or more.
- Capitalization: the SI symbol is kW, with a lowercase k. KW is incorrect, and mW (milliwatt) is a billion times smaller than MW (megawatt).
- Dividing by 100. Kilo is 1,000, so 2,500 W is 2.5 kW, not 25 kW.
- Horsepower instead: for engine or motor ratings, the kW to hp converter takes the next step.
Sources and further reading
The standards and references behind the numbers on this page. Links open in a new tab.
Standards and official sources
Further reading
- WattWikipedia
Watts to kW FAQs
Short, exact answers to what people ask most.
How many watts are in a kilowatt?
There are exactly 1,000 watts in one kilowatt.
What is 1,500 watts in kW?
1,500 W equals 1.5 kW, the rating of a typical space heater or small kettle.
What is 2,000 watts in kW?
2,000 W is 2 kW. Divide any wattage by 1,000 to get kilowatts.
How do I convert watts to kWh?
Divide watts by 1,000 to get kW, then multiply by the hours of use. A 500 W appliance used for 3 hours uses 1.5 kWh.
What is the difference between kW and kWh?
A kW is a rate of energy use (power), while a kWh is an amount of energy. Running a 1 kW device for one hour uses 1 kWh.
Is kVA the same as kW?
Only when the power factor is 1. Otherwise kW = kVA × power factor, so a 10 kVA generator at a power factor of 0.8 delivers 8 kW.
How many kW is 3,500 watts?
3,500 W is 3.5 kW.
What is 500 watts in kilowatts?
500 W equals 0.5 kW, and running it for two hours uses 1 kWh.
How many watts is 2.5 kW?
2.5 kW is 2,500 W; multiply kilowatts by 1,000 to get watts.
Related conversions
The watt and the kilo prefix are defined in the BIPM SI Brochure (9th ed.) and NIST SP 330, symbol usage follows NIST SP 811 (2008), and EV charging levels and circuit rules follow SAE J1772 and the US National Electrical Code (NFPA 70) Article 625. Last updated . How we verify our numbers.