kWh to kW Calculator
Convert between Kilowatt-hours (Energy) and Kilowatts (Power), or calculate time. Essential for sizing generators, batteries, and estimating fuel costs.
Calculator Settings
Enter utility rate or generator fuel cost equivalent.
Total Energy
Understanding Power vs. Energy
It is easy to confuse Kilowatts (kW) and Kilowatt-hours (kWh), but they measure different things. Think of it like a car trip:
- kW (Power): This is like speed (mph). It represents the rate at which electricity is being generated or consumed at this exact moment.
- kWh (Energy): This is like distance (miles). It represents the total amount of electricity generated or consumed over a period of time.
Formulas:
- Energy (kWh) = Power (kW) × Time (hours)
- Power (kW) = Energy (kWh) / Time (hours)
- Time (hours) = Energy (kWh) / Power (kW)
Common Generator Energy Production
| Generator Size | Load % | Output (kW) | Daily Energy (24h) |
|---|---|---|---|
| 2,000 W | 50% | 1.0 kW | 24 kWh |
| 5,000 W | 50% | 2.5 kW | 60 kWh |
| 10,000 W | 75% | 7.5 kW | 180 kWh |
| 20,000 W | 50% | 10.0 kW | 240 kWh |
| 50,000 W | 80% | 40.0 kW | 960 kWh |
*Assuming constant load for 24 hours.
How to Convert Between kWh and kW
With the formulas at hand, converting between power and energy is a straightforward matter of multiplication or division. As long as you keep your units aligned (hours for time, continuous kW for power), you can't go wrong.
Find Energy (kWh)
You know the power output and time.
Example: 2 kW × 5 h = 10 kWh
Find Power (kW)
You know the total energy and time.
Example: 20 kWh ÷ 4 h = 5 kW
Find Time (Hours)
You know the energy limit and power output.
Example: 5 kWh ÷ 1 kW = 5 hours
Frequently Asked Questions
What happens if I run a 5 kW generator for 12 hours?
If the generator runs at full load (5 kW) for 12 hours, you simply multiply the two. Power (5 kW) × Time (12 hours) = 60 kWh. It will produce 60 kilowatt-hours of electrical energy.
Why are batteries rated in Wh or kWh?
Batteries store energy, not just power. The kWh (or Wh) rating tells you the total amount of energy the battery can hold. For example, a 1 kWh battery can supply 1 kW of power for 1 hour, or 500 Watts for 2 hours.
Does a 2000-watt inverter draw 2 kWh?
Not inherently! A 2000-watt (2 kW) inverter is capable of delivering 2 kilowatts of power at any given second. It only consumes 2 kWh of energy if you run it at full load continuously for a full hour.
How much does a kWh of electricity cost?
In the US, the average cost of residential electricity is around 15 to 20 cents per kWh depending on your state. Running a 5 kW generator for 10 hours yields 50 kWh, which would roughly translate to $7.50 to $10.00 worth of electrical grid energy.
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