How do I convert kW to kWh?

kWh = kW × hours. Power (kW) multiplied by time (hours) gives energy (kWh). A 5 kW solar system running at full output for 4 hours produces 20 kWh. kW and kWh measure different things — you need both a power rating and a time duration to convert.

How many watts is 1 kWh?

1 kWh cannot be directly converted to watts because kWh is energy and watts is power — they measure different things. However, 1 kWh = 1,000 Wh (watt-hours). If you want to know the watt equivalent, you'd say: 1,000 watts running for 1 hour = 1 kWh.

Solar Unit Converter

Convert between watts, kilowatts, megawatts, kWh, MWh, BTU, joules, and calories — all at once.

Enter a value to convert

Value

From unit

5 kW equals:

Watts (W)5,000 W

Kilowatts (kW)5 kW

Megawatts (MW)0.005 MW

Gigawatts (GW)0.000005 GW

Horsepower (hp)6.7051 hp

BTU per hour (BTU/hr)17,060.77 BTU/hr

Link copied to clipboard

How to Use This Calculator

Choose power or energy mode

Solar involves two distinct physical quantities that are often confused. Power (watts, kilowatts, megawatts) measures the rate of energy flow at any instant — how fast energy is being produced or consumed. Energy (watt-hours, kilowatt-hours, megawatt-hours) measures the total amount of energy produced or consumed over time. A 5 kW solar system (power) running for 4 hours produces 20 kWh (energy).

Enter a value and select the source unit

Type any number in the value field, select the unit you're converting from, and all conversions appear instantly. The current input unit is highlighted in teal. This works for any direction — enter kWh and get Wh, MWh, BTU, joules, and calories all at once.

Common solar conversions

Installers quote system sizes in kW or kWp (kilowatt-peak). Utility bills are in kWh. Grid-scale systems are quoted in MW or GW. Heat pumps and AC units are rated in BTU/hr for power. Battery capacity is usually in kWh.

Quick Reference — Power Units

1 kW = 1,000 W 1 MW = 1,000 kW = 1,000,000 W 1 GW = 1,000 MW = 1,000,000 kW 1 hp = 745.7 W (mechanical horsepower) 1 BTU/hr = 0.293 W Solar system sizes: Residential: 3–15 kW Commercial: 15–500 kW Utility-scale: 1 MW – 5 GW

Quick Reference — Energy Units

1 kWh = 1,000 Wh 1 MWh = 1,000 kWh = 1,000,000 Wh 1 GWh = 1,000 MWh = 1,000,000 kWh 1 kWh = 3,412 BTU 1 kWh = 3,600,000 J = 3,600 kJ = 3.6 MJ 1 kWh = 860 kcal = 860,000 cal Common energy quantities: Monthly home usage (US avg): ~900 kWh EV full charge (Tesla Model 3): ~75 kWh AA battery: ~3 Wh 1 gallon gasoline energy-equivalent: ~33.7 kWh

FAQ

What is the difference between kW and kWh in solar? ▼

kW (kilowatt) is a measure of power — the rate of energy production at any given moment. Your solar system's "size" is in kW: a 6 kW system can produce 6 kW of electricity when the sun shines at full intensity. kWh (kilowatt-hour) is a measure of energy — the total electricity produced or consumed over time. Your utility bill is in kWh. The formula: kWh = kW × hours. A 6 kW system running at full output for 5 hours produces 30 kWh.

How do I convert BTU to kWh for an air conditioner? ▼

AC units are rated in BTU/hr (cooling capacity). To convert to kW of cooling: divide BTU/hr by 3,412. A 12,000 BTU/hr (1-ton) AC has 3.5 kW of cooling capacity. However, this is cooling power — the electrical power consumed depends on the SEER efficiency rating. A 12,000 BTU/hr AC with SEER 16 consumes about 750W of electricity. Use our AC Cost Calculator to calculate actual electricity consumption.

What does kWp mean — is it the same as kW? ▼

kWp (kilowatt-peak) is the rated capacity of a solar panel under Standard Test Conditions (STC): 1,000 W/m² irradiance, 25°C cell temperature, AM 1.5 spectrum. In practice, panels rarely hit their peak rating because real-world conditions differ from STC. kWp is used to describe panel and system capacity; actual output in kW at any moment is typically 70-90% of the kWp rating on a good sunny day. For energy calculations, use kWh (production) not kWp (rated capacity).

How many kWh is a megajoule? ▼

1 megajoule (MJ) = 0.2778 kWh. Equivalently, 1 kWh = 3.6 MJ. Joules are the SI unit of energy used in physics and engineering; kilowatt-hours are the practical unit used in electricity billing and solar production. Both measure the same physical quantity (energy) in different units. The conversion: 1 kWh = 3,600,000 joules = 3,600 kJ = 3.6 MJ.