Kilowatt to Watt Converter

This kilowatt to watt converter changes kW to W instantly and shows the same power in megawatts, horsepower and BTU per hour. Type a value in kilowatts; for the reverse (watts to kW), divide by 1,000 or read across the table below.

How to convert kilowatts to watts

The kilo- prefix in the International System of Units (SI) means one thousand (NIST SI prefixes), so:

• Watts = kilowatts × 1,000
• Kilowatts = watts ÷ 1,000
• Megawatts = kilowatts ÷ 1,000
• Horsepower = kilowatts ÷ 0.7457 (1 mechanical hp ≈ 745.7 W, NIST SP 811 Appendix B)
• BTU per hour = kilowatts × 3,412.14 (EIA rounds this to 3,412)

Worked example with the default value

1. Input: 1.5 kW (a typical space heater or hair dryer rating)
2. Watts: 1.5 × 1,000 = 1,500 W
3. Megawatts: 1.5 ÷ 1,000 = 0.0015 MW
4. Horsepower: 1.5 ÷ 0.7457 = 2.012 hp
5. BTU/h: 1.5 × 3,412.14 = 5,118 BTU/h
6. Energy if run for one hour: 1.5 kWh

kW to W conversion table

Watts to kW table

Kilowatt vs watt: what’s the difference?

A kilowatt and a watt measure the same thing, power, at different scales: 1 kW is 1,000 W. Watts suit small devices such as a 10 W LED bulb; kilowatts suit larger loads such as a 7.2 kW EV charger or a 10 kW solar system. Neither is energy; for that you need kilowatt-hours.

kW vs kWh: the mix-up to avoid

Kilowatts measure power, how fast energy flows right now. Kilowatt-hours measure energy, the total over time. A 1.5 kW heater uses 1.5 kWh each hour it runs, so after 4 hours it has used 6 kWh. So 1 kilowatt does not equal 1 kilowatt-hour; it equals 1 kWh only after one hour of use. To get energy from power and time, use the watts to kWh calculator. For a full explanation, read what is a kilowatt-hour.

Where you see kW and W

• Appliances list watts on the label: kettles, microwaves and heaters often run between 1,000 and 3,000 W.
• Solar panels are rated in watts per panel and kilowatts per system (kW DC).
• EV chargers are rated in kW. Level 2 home chargers are a few kW; DC fast chargers run much higher.
• Power plants and wind turbines use megawatts (MW) and gigawatts (GW), the scale of utility renewable energy projects.

Step-by-step: converting any power rating

1. Find the rating on the label or spec sheet and note its unit (W, kW, MW, hp or BTU/h).
2. Convert to watts first: kW × 1,000, MW × 1,000,000, hp × 745.7, BTU/h ÷ 3.41214.
3. Convert from watts to the unit you need by reversing the same factor.
4. To find energy, multiply the power by the hours of use and divide by 1,000 for kWh.

Common kW ratings around the home

Power ratings show up on almost every large appliance and energy system. Kitchen appliances and space heaters usually list watts on the nameplate, while central air conditioners and furnaces list BTU/h or tons. Solar inverters, home batteries and EV chargers list kW because their ratings run into the thousands of watts. When you compare a battery’s kW rating with its kWh capacity, the kW tells you how much it can power at once and the kWh tells you for how long. A battery rated 5 kW and 10 kWh, for example, can run a 5 kW load for about two hours.

History: James Watt and the horsepower

The two power units on this page share a history. James Watt, the Scottish engineer who improved the steam engine, needed a way to sell engines to customers who used horses. He found by experiment in 1782 that a mill horse could do about 32,400 foot-pounds of work per minute, and Watt and Matthew Boulton standardised the figure at 33,000 ft·lbf per minute, the mechanical horsepower still used today (Horsepower). That works out to about 745.7 W. A century later, in 1882, C. William Siemens proposed naming the electrical unit of power after Watt himself (Watt (unit)), and the watt became the SI unit of power in 1960.

References

• Thompson, A. & Taylor, B. N. (2008). Guide for the Use of the International System of Units (SI). NIST Special Publication 811. doi:10.6028/NIST.SP.811e2008
• BIPM (2019). The International System of Units (SI Brochure), 9th edition. Bureau International des Poids et Mesures. bipm.org

Quick mental math

Moving between watts and kilowatts is just a decimal shift of three places. To go from kW to W, move the decimal point three places right: 2.5 kW becomes 2,500 W. To go from W to kW, move it three places left: 850 W becomes 0.85 kW. The same shift takes you from kW to MW and from MW to GW, which is how utility-scale plants are reported.