Electricity Cost Calculator
Estimate the running cost of an appliance from wattage, hours of use, and your cost per kWh.
How to use this electricity cost calculator
- Enter the appliance wattage
Find the Wattage on the nameplate or product manual and enter it in watts.
- Set daily usage
Enter Hours per day — how many hours the appliance runs on a typical day.
- Add your electricity rate
Enter your Cost per kWh from your utility bill or provider's rate schedule.
- Read the cost results
The calculator shows Daily cost, Monthly cost, and Annual cost.
- Compare appliances
Run the calculation for different devices to see which ones drive your bill highest.
How this electricity cost calculator works
This electricity cost calculator converts appliance wattage into energy use over time, then applies your electricity rate to estimate daily, monthly, and annual running costs. It is useful when comparing appliances, checking whether a device is expensive to run, or building a household energy budget.
Energy cost = (wattage ÷ 1000) × hours used × cost per kWh A 1,500 W space heater running 4 hours per day at $0.15 per kWh costs $0.90 per day. Over a 30-day month that is $27.00, and over a full year $328.50. By comparison, a 60 W fan or similar low-draw device running the same 4 hours costs only $0.036 per day — roughly $1.08 per month — making the heater about 25 times more expensive to operate.
A 1,500 W space heater running 4 hours per day at $0.15 per kWh costs $0.90 daily, $27.00 monthly, and $328.50 annually. A 60 W fan running the same 4 hours costs only $0.036 per day — about 25 times less.
Devices with similar wattage can have very different costs based on usage. A 1,500 W heater used 4 hours daily costs $328.50 per year; the same heater used half as many hours would cost roughly half that — usage patterns matter as much as wattage.
- ✓ The appliance is assumed to draw roughly the same wattage during the hours you enter.
- ✓ Your electricity rate is treated as constant, even though some providers use tiered or time-of-use pricing.
- ✓ Standby power and efficiency differences are not included unless you reflect them in the wattage input.
- High-wattage appliances used for short periods can still create noticeable monthly cost, especially at higher electricity rates.
- Check the actual nameplate or product manual if you want a better estimate than a rough average wattage.
- National and regional electricity tariff references
- Consumer energy-efficiency guidance on appliance use and kWh calculations
How kWh pricing and usage drive electricity cost
Electricity cost is driven by three factors: wattage (power draw), hours of use, and the rate you pay per kilowatt-hour. Wattage is the instantaneous power the device uses when running. A 1500 W heater draws 1.5 kW; running it for 4 hours consumes 1.5 × 4 = 6 kWh. Multiply that by your cost per kWh to get the daily cost. Rates vary widely by region, time of day (if you have time-of-use pricing), and tier (if usage above a threshold costs more). The calculator assumes a flat rate, so for tiered or time-of-use plans the result is an approximation. High-wattage appliances used briefly — like a kettle or toaster — can cost less per month than medium-wattage devices left on for hours — like an old desktop computer or space heater. Usage patterns matter as much as wattage when building a household energy budget.
Savings strategies for electricity cost
The most effective way to cut electricity cost is to reduce hours of use for high-wattage devices. A 1500 W space heater running 4 hours per day costs far more than a 60 W fan running the same time. Switching to a heat pump or more efficient heater can cut wattage by half or more for the same heating output. For always-on devices like refrigerators and routers, upgrading to Energy Star or more efficient models reduces the constant draw. Unplugging or using smart strips for phantom loads — TVs, chargers, and game consoles that draw power when 'off' — can save 5–10% of a household bill. Running high-use appliances during off-peak hours, if your utility offers time-of-use rates, lowers the effective cost per kWh. Finally, comparing the calculator output across your main appliances helps you prioritize which upgrades or behavior changes will have the biggest impact.
Electricity cost calculator FAQs
What does kWh mean?
kWh stands for kilowatt-hour, which is the unit utilities use to measure energy consumption over time.
Why does wattage have to be divided by 1000?
Because electricity rates are commonly priced per kilowatt-hour, and 1000 watts equals 1 kilowatt.
Can I use this for any appliance?
Yes, as long as you have a reasonable estimate of its wattage and typical daily usage time.
Why might the real bill be different?
Real bills can differ because of variable power draw, tiered utility pricing, standby power, and seasonal rate changes.
How can I compare appliances with this calculator?
Enter the wattage and usage assumptions for each device and compare the monthly or annual cost outputs.