Home Power Consumption Calculator
Calculate your home electricity usage and cost.
Add appliances with their wattage and daily hours to estimate monthly kWh and electric bill.
Electricity consumption and cost are calculated using kilowatt-hours (kWh) — the standard unit on your electricity bill. One kilowatt-hour equals 1,000 watts running for 1 hour.
Core formulas:
Daily kWh = (Wattage × Hours Used per Day) / 1,000
Monthly kWh = Daily kWh × 30
Monthly Cost = Monthly kWh × Electricity Rate ($/kWh)
Annual Cost = Monthly Cost × 12
Common appliance wattages and monthly costs (at $0.16/kWh, US average):
| Appliance | Watts | Daily Hours | Monthly kWh | Monthly Cost |
|---|---|---|---|---|
| LED bulb | 10 | 6 | 1.8 | $0.29 |
| Phone charger | 5 | 3 | 0.45 | $0.07 |
| Laptop | 60 | 6 | 10.8 | $1.73 |
| Desktop + monitor | 250 | 6 | 45 | $7.20 |
| Refrigerator | 150 | 24 | 108 | $17.28 |
| 55" LED TV | 80 | 5 | 12 | $1.92 |
| Washing machine | 500 | 1 | 15 | $2.40 |
| Clothes dryer | 3,000 | 1 | 90 | $14.40 |
| Dishwasher | 1,800 | 1 | 54 | $8.64 |
| Central AC (2-ton) | 2,500 | 6 | 450 | $72.00 |
| Space heater | 1,500 | 4 | 180 | $28.80 |
| Electric water heater | 4,500 | 3 | 405 | $64.80 |
US electricity rates by state range (2025): $0.10/kWh (Louisiana) to $0.35+/kWh (Hawaii, California)
Worked example: Central AC running 6 hours/day for 4 summer months at $0.22/kWh: Monthly kWh = 2,500 × 6 / 1,000 × 30 = 450 kWh 4-month cost = 450 × 4 × $0.22 = $396
Top energy-saving tips:
- Replace incandescent bulbs with LED — saves ~85% per bulb
- Unplug chargers and electronics when not in use (phantom load can be 5–10% of the bill)
- Raise the AC thermostat by 1°F — saves ~3% on cooling costs
- Switch to cold-water laundry — 90% of washing machine energy heats the water
- Air-dry dishes instead of using the dishwasher’s heated dry cycle