kW to kWh Conversion Guide
Everything You Need to Convert Kilowatts to Kilowatt-Hours
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kW to kWh Master Guide
Homeowner Savings Tip: The "Time-of-Use" Power Play
While your appliances have fixed kW ratings, your utility might charge different $/kWh rates based on when you use them. Shifting the use of high-kW devices (like your 4.5kW dryer) to "Off-Peak" hours can save you 15-30% on your total bill without reducing your actual energy consumption.
1. What Is the Difference Between kW and kWh?
kW (kilowatt) measures power — the rate at which electricity is being used right now. kWh (kilowatt-hour) measures energy — the total electricity consumed over time. Your electricity bill charges you for kWh, not kW.
| Term | Measures | Found On | Example |
|---|---|---|---|
| kW (Kilowatt) | Power — rate of energy use | Device label / spec sheet | A 2kW kettle |
| kWh (Kilowatt-Hour) | Energy — total consumed | Your electricity bill | 2kW × 1 hour = 2 kWh |
| Watt (W) | Smaller power unit | Device label | 1,000W = 1 kW |
| MWh (Megawatt-Hour) | Large energy unit | Utility/grid reports | 1,000 kWh = 1 MWh |
2. The kW to kWh Formula
The standard formula is straightforward, but it's important to ensure your units are correct before calculating.
If you have watts instead of kW, you must divide by 1,000 first:
Worked Examples
Example 1: Electric Oven
3kW running for 1.5 hours:
kWh = 3 kW × 1.5 hours = 4.5 kWh
Cost at $0.13/kWh: $0.59
Example 2: Air Conditioner
3.5kW running for 8 hours/day:
kWh = 3.5 kW × 8 hours = 28 kWh/day
Monthly cost ($0.13/kWh): $109.20
3. kW to kWh Reference Table
Use this table to convert any common kW rating without doing the math.
| kW Rating | 1 Hour | 2 Hours | 4 Hours | 8 Hours | 24 Hours |
|---|---|---|---|---|---|
| 0.1 kW (100W) | 0.1 kWh | 0.2 kWh | 0.4 kWh | 0.8 kWh | 2.4 kWh |
| 0.5 kW (500W) | 0.5 kWh | 1.0 kWh | 2.0 kWh | 4.0 kWh | 12.0 kWh |
| 1.0 kW | 1.0 kWh | 2.0 kWh | 4.0 kWh | 8.0 kWh | 24.0 kWh |
| 1.5 kW | 1.5 kWh | 3.0 kWh | 6.0 kWh | 12.0 kWh | 36.0 kWh |
| 2.0 kW | 2.0 kWh | 4.0 kWh | 8.0 kWh | 16.0 kWh | 48.0 kWh |
| 3.0 kW | 3.0 kWh | 6.0 kWh | 12.0 kWh | 24.0 kWh | 72.0 kWh |
| 3.5 kW | 3.5 kWh | 7.0 kWh | 14.0 kWh | 28.0 kWh | 84.0 kWh |
| 5.0 kW | 5.0 kWh | 10.0 kWh | 20.0 kWh | 40.0 kWh | 120.0 kWh |
| 7.2 kW | 7.2 kWh | 14.4 kWh | 28.8 kWh | 57.6 kWh | 172.8 kWh |
| 10.0 kW | 10.0 kWh | 20.0 kWh | 40.0 kWh | 80.0 kWh | 240.0 kWh |
4. Real Appliance kW Ratings and Monthly kWh Cost
Understanding the kW rating of common appliances helps you predict your monthly bill and identify energy vampires.
| Appliance | kW Rating | Daily Use | Daily kWh | Monthly kWh | Est. Cost ($0.13) |
|---|---|---|---|---|---|
| Space heater | 1.5 kW | 6 hrs | 9 kWh | 270 kWh | $35.10 |
| Central AC | 3.5 kW | 8 hrs | 28 kWh | 840 kWh | $109.20 |
| Electric oven | 2.5 kW (avg) | 1 hr | 2.5 kWh | 75 kWh | $9.75 |
| Electric water heater | 4.5 kW | 3 hrs | 13.5 kWh | 405 kWh | $52.65 |
| Washing machine | 0.5 kW | 1 hr | 0.5 kWh | 15 kWh | $1.95 |
| Electric dryer | 4.5 kW | 1 hr | 4.5 kWh | 135 kWh | $17.55 |
| Refrigerator | 0.15 kW | 8 hrs (cycle) | 1.2 kWh | 36 kWh | $4.68 |
| Gaming PC | 0.4 kW | 4 hrs | 1.6 kWh | 48 kWh | $6.24 |
| EV charger (L2) | 7.2 kW | 3 hrs | 21.6 kWh | 324 kWh | $42.12 |
| Pool pump | 1.5 kW | 8 hrs | 12 kWh | 360 kWh | $46.80 |
5. Converting kWh Back to kW
If you know the total energy used (kWh) and the time, you can find the average power draw in kilowatts.
Example: Your home used 600 kWh in 30 days (720 hours).
600 kWh ÷ 720 hours = 0.833 kW average continuous draw.
That equals 833 watts running non-stop all month.