How to use the electricity cost calculator
- Add a row for each appliance and enter its watts, hours of use per day and quantity.
- Enter your price per kWh. Divide your bill total by the kWh used to get the all-in rate, including delivery and taxes.
- Read the daily, monthly and yearly cost, and the breakdown that shows which appliance costs the most.
The formula
kWh per day = Watts × Hours per day × Quantity ÷ 1,000 Cost per day = kWh per day × Price per kWh Cost per month = Cost per day × Days used Cost per year = Cost per day × 365
Worked example
- TV: 100 W × 5 h ÷ 1,000 = 0.5 kWh/day
- Space heater: 1,500 W × 2 h ÷ 1,000 = 3 kWh/day
- Total 3.5 kWh/day × 30 days = 105 kWh → at $0.16/kWh = $16.80 per month, $204.40 per year
Typical appliance wattage
| Appliance | Typical watts | Typical use | Cost/month at 17¢ |
|---|---|---|---|
| LED bulb (60 W equivalent) | 9 W | 5 h/day | $0.23 |
| Refrigerator (compressor) | 150 W | 8 h/day | $6.12 |
| Window air conditioner | 1,000 W | 8 h/day | $40.80 |
| Space heater | 1,500 W | 4 h/day | $30.60 |
| Electric clothes dryer | 5,000 W | 1 h/day | $25.50 |
| Desktop gaming PC | 400 W | 4 h/day | $8.16 |
| 50-inch LED TV | 100 W | 5 h/day | $2.55 |
| Electric water heater | 4,500 W | 3 h/day | $68.85 |
Real use varies a lot with model, settings and climate — a plug-in watt meter shows what your own appliances draw.
How to lower your electric bill
- Target heating and cooling first: space heaters, air conditioning, water heaters and dryers are usually the biggest loads.
- Switch to LED bulbs — they use about 75–85% less energy than incandescent bulbs.
- Check for time-of-use rates: running the dishwasher, dryer or EV charger at night can cost much less.
- Kill standby power with smart power strips on TV and computer setups.
- Replace old appliances: a 20-year-old fridge can use twice the energy of a new ENERGY STAR model.
Reading your bill
US bills often split the cost into a supply (generation) charge and a delivery charge, plus a fixed monthly customer charge. For this calculator, use the per-kWh total of supply and delivery; the fixed charge doesn’t change with use. Many countries quote prices in cents or pence per kWh — enter 0.30 for 30 c/kWh.
Amps instead of watts?
If the label only shows current, multiply amps by the supply voltage: a 10 A appliance on a 120 V US outlet draws about 1,200 W, and on a 230 V supply about 2,300 W. Motors and compressors draw more for a moment when they start, but that short surge barely affects the monthly cost.