Electrical basics
Appliance energy consumption calculator
Enter the appliance power, hours of use per day and number of days to see the approximate energy use (kWh). If you enter your own unit price, an approximate cost is shown too.
Loading calculator…
Tariffs, taxes and price tiers are not included; you enter the unit price yourself. Cost is simply kWh × your unit price.
How is it calculated?
Energy use is power times operating time times the load factor. The load factor is the average share of rated power the appliance draws while running.
Energy use
E = P_W × h × d × LF / 1000
P_W: power (W), h: hours per day, d: number of days, LF: load factor (0–1), E: kWh.
Cost (optional)
Cost = E × unit price
You enter the unit price; tariffs, taxes and tiers are not included.
Example
- Inputs: P = 2000 W, 3 hours per day, 30 days, load factor 1.
- Energy use: 2000 × 3 × 30 × 1 / 1000 = 180 kWh.
- No unit price entered, so no cost is shown.
The example inputs are for illustration only; they are not verified defaults. Results are approximate and do not replace engineering advice.
Frequently asked questions
What is the load factor and what should I enter?
It is the average share of the rated power the appliance draws while running. A heater running at full power is about 1; thermostat-controlled or variable devices are lower.
Why may this differ from my bill?
Bills include tariffs, tiers, network charges and taxes, which this calculation leaves out. Real power and usage time may also differ from your estimate.
Is standby consumption included?
No. Calculate standby as a separate line with the standby power and hours.