Power & Energy
Unit Converter
Convert between watts, kilowatts, watt-hours, amp-hours and other electrical energy units.
Perfect for batteries, generators, solar, EVs, HVAC, and home backup sizing.
Watt ↔ Kilowatt
Watt-hour ↔ Kilowatt-hour
Kilowatt ↔ BTU per hour
Kilowatt ↔ Mechanical Horsepower
Ampere-hour ↔ Watt-hour
Watt ↔ Ampere
Kilowatt ↔ Ampere
Kilovolt-Ampere ↔ Kilowatt
BTU per hour ↔ Refrigeration Ton
Miles per kWh ↔ kWh per 100 miles
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View all converter categoriesUnderstand Power & Energy Basics
Power vs Energy
Power (Watts, kW) is the rate of energy use. Energy (Wh, kWh) is the total amount used over time. A 1 kW appliance running for 2 hours consumes 2 kWh.
Why Voltage Matters
To convert Watts (real power) to Amps (current), you must know the Voltage. A 1000W appliance pulls twice the Amps at 120V than it does at 240V.
Ah vs Wh for Batteries
Amp-hours (Ah) is charge capacity. Watt-hours (Wh) is true energy capacity. You must multiply Ah by the battery's nominal voltage to find Wh.
BTU/hr vs Electrical Input
12,000 BTU/hr equals 1 refrigeration ton of cooling. It does not equal 3.5 kW of electrical draw. Air conditioners use less input power due to their efficiency (COP).
Put your numbers to work.
Now that you've converted your units, estimate your actual running costs or build a complete home energy profile.