Watts to kW Calculator
Convert watts to kilowatts. Divide by 1,000. Live calculator and reference table for common appliance wattages.
Common conversions
| Input | Result |
|---|---|
| 10 W | 0.01 kW |
| 25 W | 0.025 kW |
| 60 W | 0.06 kW |
| 100 W | 0.1 kW |
| 500 W | 0.5 kW |
| 1,500 W | 1.5 kW |
| 3,000 W | 3 kW |
| 5,000 W | 5 kW |
| 10,000 W | 10 kW |
| 50,000 W | 50 kW |
The math behind it
- Total watts = 1500 + 1200 + 800
- Total = 3500 W
- kW = 3500 / 1000
- kW = 3.5
Everything you need to know
A watt is the base unit of power in the metric system, and a kilowatt is just 1,000 of them. To convert watts to kilowatts, divide the wattage by 1,000. That single division is all the math requires; the rest of this page is about knowing when a number belongs in watts versus kilowatts and reading real equipment labels correctly.
How the metric power prefixes line up
Power units on the metric scale move in steps of 1,000. A milliwatt (mW) is one-thousandth of a watt, used for things like a phone's Bluetooth radio (1-100 mW) or a laser pointer (under 5 mW). The watt (W) is the base unit. A kilowatt (kW) is 1,000 watts, the unit used for household appliances and home electrical service. A megawatt (MW) is 1,000 kilowatts, or 1,000,000 watts, the scale used for power plants and solar farms. Because each step is exactly a factor of 1,000, converting between any two of these units is just moving the decimal point three places per step.
Where watt-level ratings show up
Watts are the right unit for small electronics and single appliances. An LED bulb typically draws 8 to 15 watts (a 60-watt-equivalent LED usually pulls about 9 W). A phone charger ranges from 5 W for a basic USB brick to 25 W or more for fast charging, while laptop chargers and USB-C power adapters run 45 to 100 W. A box fan draws roughly 60 to 100 W, a desktop computer 200 to 500 W, a microwave 700 to 1,200 W, and a hair dryer 1,200 to 1,875 W. A portable space heater tops out near 1,500 W, which is close to the maximum continuous load on a standard US 15 A, 120 V household circuit (1,800 W).
Once a household adds up several of these ratings, the total quickly crosses into four digits, and that's the point where converting to kilowatts makes the number easier to work with. A home's electrical service is also sized in kilowatts: a 200 A, 240 V panel supports roughly 48 kW of instantaneous load, so comparing a handful of watt-rated appliances against that figure means dividing each one by 1,000 first.
Worked example: adding up a kitchen's load
Suppose a microwave (1,500 W), a toaster oven (1,200 W), and a blender (800 W) all run at the same moment. Add the watt ratings: 1,500 + 1,200 + 800 = 3,500 W. Divide by 1,000 to convert: 3,500 / 1,000 = 3.5 kW. That 3.5 kW instantaneous draw can then be checked against a 15 kW or 20 kW kitchen sub-panel, or against a home's total service capacity, in the same units.
Common applications
Utility bills, solar quotes, and home energy audits are all expressed in kW or kWh. Converting a 1,500 W microwave to 1.5 kW lets it slot directly into that spreadsheet alongside everything else.
Panel labels read in watts, commonly 350 to 450 W each. Twenty 400 W panels total 8,000 W; divide by 1,000 to get the array's 8 kW DC rating, which is what installers quote and permit.
Server power supplies are rated in watts, often 500 to 1,200 W each. Summing a rack's PSU wattage and converting to kW is how facilities check the load against PDU and cooling capacity, which are specified in kW.
Adding up watt-rated appliances (oven, dryer, AC, EV charger) and converting the total to kW shows how close a household sits to its 24 kW or 48 kW service limit before adding a new circuit.
Common mistakes
1,500 W is the instantaneous rate of power draw; 1,500 Wh is the energy consumed over one hour at that rate. The conversion to kW or kWh is the same division by 1,000, but the two units measure different things.
Dividing by 100 instead of 1,000 turns a 1,500 W space heater into a false 15 kW reading, an error large enough to make a load calculation look like it will overload a panel that's actually fine.
1,000 milliwatts equal 1 watt, not 1,000 watts. Treating a 100 mW Bluetooth radio as 100 W overstates its power draw by a factor of 1,000.
Motors and compressors (refrigerators, AC units, well pumps) list a startup surge watt figure that can be 2 to 3 times the running wattage. Convert the running wattage to kW for continuous load calculations, and check the surge figure separately for generator sizing.
Frequently asked questions
How many watts are in 1 kilowatt?+
1,000 watts equal 1 kilowatt. The kilo- prefix always means 1,000 in the metric system, so kW is simply W divided by 1,000.
Is 1,500 watts the same as 1.5 kW?+
Yes. 1,500 W divided by 1,000 equals 1.5 kW exactly; nothing about the actual power draw changes, only the unit used to describe it.
How do I convert watts to kW without a calculator?+
Move the decimal point three places to the left. 2,500 W becomes 2.5 kW, and 750 W becomes 0.75 kW.
Is a 100-watt light bulb equal to 0.1 kW?+
Yes, 100 W divided by 1,000 is 0.1 kW. Most LED bulbs today draw far less, around 8 to 15 W, or 0.008 to 0.015 kW.
How many watts is a typical US home's electrical service?+
A 200 A, 240 V panel supports about 48,000 W, or 48 kW, of instantaneous capacity. Older 100 A services support roughly 24 kW.
Does converting watts to kW change how much power is actually used?+
No. Converting units does not change the physical quantity, it only rescales the number. 3,500 W and 3.5 kW describe the exact same power.
Is a milliwatt the same as 0.001 watts?+
Yes. A milliwatt is one-thousandth of a watt, the same relationship kilowatts have to watts, just one step down the scale instead of up.
How many kilowatts does a hair dryer use?+
Most hair dryers draw 1,200 to 1,875 watts, which is 1.2 to 1.875 kW. Check the wattage printed on the handle or base for the exact figure.
Why do solar panel labels list watts but system size is quoted in kW?+
Individual panels are small enough that watts are a convenient label (commonly 350-450 W each), but a full array of 20 or more panels adds up to several thousand watts, so installers convert the total to kW to match utility and permitting paperwork.