kW to kWh Calculator
Kilowatts measure power (how fast energy flows). Kilowatt-hours measure energy (how much is used). There is no direct conversion: you must supply a time. Formula: kWh = kW x hours.
kW to kWh
Presets are typical values only. Actual draw varies by brand, model, and settings.
kWh to kW (reverse)
Find the average power from a known energy total and duration.
Formula
1 kWh = 1000 Wh = 3,600,000 J exactly.
Quick reference table
Energy in kWh for common power ratings over 1 hour, 8 hours, and 24 hours.
| Power | 1 hour | 8 hours | 24 hours |
|---|---|---|---|
| 0.1 kW | 0.1 | 0.8 | 2.4 |
| 0.25 kW | 0.25 | 2 | 6 |
| 0.5 kW | 0.5 | 4 | 12 |
| 0.75 kW | 0.75 | 6 | 18 |
| 1 kW | 1 | 8 | 24 |
| 1.5 kW | 1.5 | 12 | 36 |
| 2 kW | 2 | 16 | 48 |
| 3 kW | 3 | 24 | 72 |
| 5 kW | 5 | 40 | 120 |
| 10 kW | 10 | 80 | 240 |
Worked examples
1. 1 kW for 24 hours. 1 kW x 24 h = 24 kWh. At $0.15 per kWh the cost is 24 kWh x $0.15 = $3.60 per day.
2. 5 kW for 1 hour. 5 kW x 1 h = 5 kWh, costing 5 kWh x $0.15 = $0.75.
3. Air conditioner, 1 PK (0.74 kW), 8 hours a day. 0.74 kW x 8 h = 5.92 kWh per day. Daily cost at $0.15 per kWh: 5.92 kWh x $0.15 = $0.888. Over a 30-day month: 5.92 x 30 = 177.6 kWh, costing $26.64. Over a year of daily use: $324.12. Equivalent energy: 5.92 kWh = 5920 Wh = 21312000 J.
4. Reverse: monthly bill of 450 kWh over 30 days. 30 days = 720 hours. Average power = 450 kWh / 720 h = 0.625 kW, which is 625 W of continuous draw.
- Small devices in watts (phone chargers, laptops): use the watts-to-wh calculator.
- Battery capacity in amp-hours: use the ah-to-kwh-calculator.
- Full electricity bill with tiers and fees: use the energy-cost-calculator.
- Megawatt / gigawatt scale grid numbers: use the megawatt-to-kwh-calculator.
- kW to kVA needs a power factor and is a different question from kW to kWh.
Related calculators
Frequently asked questions
What is the formula to convert kW to kWh?
kWh = kW x hours. Multiply the power in kilowatts by the time in hours. Example: a 2 kW heater running for 3 hours uses 2 x 3 = 6 kWh.
How much is 1 kW in kWh?
It depends on the time. 1 kW running for 1 hour is 1 kWh, and 1 kW running for 24 hours is 24 kWh. Without a duration, kW cannot be expressed as kWh.
How do I convert 5 kW to kWh?
Multiply by the hours of use. 5 kW for 1 hour is 5 x 1 = 5 kWh; the same 5 kW load for 8 hours is 5 x 8 = 40 kWh.
What is the difference between kW and kWh?
kW (kilowatt) is power, the rate at which energy flows. kWh (kilowatt-hour) is energy, the total amount delivered. Think of kW as speed and kWh as distance: speed alone does not tell you how far you went until you know the time.
Why can you not convert kW to kWh directly?
They measure different physical quantities. kW is power (energy per unit time) and kWh is energy. A time input is always required, which is why this calculator asks for a duration.
How do I convert kWh back to kW?
kW = kWh divided by hours. This gives the average power over that period. Example: 450 kWh used over 30 days (720 hours) means an average draw of 450 / 720 = 0.625 kW, or 625 W.
How do I calculate kWh per day?
Multiply the device power in kW by the hours it runs each day. A 0.74 kW (1 PK) air conditioner running 8 hours a day uses 0.74 x 8 = 5.92 kWh per day.
How do I estimate my electricity cost?
Multiply the kWh by your tariff per kWh: cost = kWh x tariff. At $0.15 per kWh, the 5.92 kWh per day from the air conditioner example costs 5.92 x 0.15 = $0.888 per day, about $26.64 per month if used daily.
How many kWh does a 1 PK air conditioner use?
A 1 PK unit draws about 0.74 kW. Over 8 hours that is 0.74 x 8 = 5.92 kWh. Actual consumption varies with temperature setting, room size, and inverter versus non-inverter models, so treat 0.74 kW as a typical value.
What does 1 kWh feel like in everyday terms?
1 kWh runs a 1000 W heater for one hour, a 100 W bulb for ten hours, or charges a typical smartphone about 60 to 80 times. In SI units, 1 kWh equals exactly 3,600,000 joules.
Is kWh the same as a unit of electricity?
Yes, in many countries one billing unit equals 1 kWh. If your bill shows 450 units, that is 450 kWh.
What is the difference between kW and kVA?
kVA is apparent power and kW is real power; they are linked by the power factor: kW = kVA x power factor. For a purely resistive load the power factor is 1, so kW equals kVA, but for motors and electronics they differ.
Does standby power consumption matter?
Yes, small loads add up over 24 hours. A 5 W standby device uses 0.005 x 24 = 0.12 kWh per day, about 3.6 kWh per month.
How can I reduce my kWh usage?
Cut hours of use, switch to efficient appliances, and fix the biggest loads first: heating, cooling, and water heating usually dominate a bill. Measure each device with this calculator to rank them by kWh before spending money on upgrades.
Which related calculator should I use?
For watt-scale devices use the watts-to-wh calculator, for battery capacity the ah-to-kwh-calculator, for a full bill breakdown the energy-cost-calculator, and for megawatt-scale grid numbers the megawatt-to-kwh-calculator.
Free tool by NRTechStudio