Home energy planning
Electricity Usage Calculator
Estimate how much electricity an appliance or group of appliances uses each day, month and year. Start with a practical preset, then adjust the schedule or enter an energy-label value.
Electricity Planning
Single Appliance Usage
Typical estimate — adjust to match your actual usage.
Advanced settings
Example rate — replace with your actual rate.
Estimated Appliance Use
100 W × 4 hours/day × 7 days/week = 2.80 kWh/week.
What if I use this appliance 1 hour less per day?
146.1 kWh/year → 109.6 kWh/year
Potential savings: 36.5 kWh/yearHow to calculate electricity usage
For power-based estimates, watts × hours per day × days per week × duty cycle gives weekly energy. The calculator then normalizes that result to 365.25 days for daily, monthly and annual views.
Watts to kWh
Divide watt-hours by 1,000 to convert to kilowatt-hours. A 100 W television used for four hours per day, seven days per week uses 2.8 kWh per week, or about 146.1 kWh per year.
Using cycles and energy labels
Use energy per cycle when a device provides a measured cycle value. Energy-label values are authoritative: the calculator applies quantity, then derives the other time periods without applying a second wattage or schedule assumption.
Top household appliances electricity usage breakdown
Typical continuous watts, operating schedules, and monthly electricity consumption for common residential appliances:
| Appliance | Running Watts | Typical Daily Use | Est. Monthly kWh | Est. Monthly Cost (@ $0.16/kWh) |
|---|---|---|---|---|
| Central Air Conditioning (3-ton, 14 SEER) | 3,500 W | 6 hours/day (cycling) | ~630 kWh | ~$100.80 |
| Water Heater (50-gallon electric tank) | 4,500 W | 3 hours/day (cycling) | ~405 kWh | ~$64.80 |
| Electric Space Heater | 1,500 W | 8 hours/day | ~360 kWh | ~$57.60 |
| Standard Kitchen Refrigerator (22 cu. ft.) | 150 W (running) | 24 hrs (33% duty cycle) | ~36 kWh | ~$5.76 |
| Level 2 EV Home Charger | 7,200 W (30A @ 240V) | 2.5 hours/day (30 mi/day) | ~540 kWh | ~$86.40 |
| Electric Clothes Dryer | 3,000 W | 1 cycle/day (45 min) | ~68 kWh | ~$10.88 |
| Home Desktop Computer / Gaming PC | 300 W | 6 hours/day | ~54 kWh | ~$8.64 |
Electricity Usage & Appliance Energy Formulas
Converts instantaneous appliance power demand into normalized daily, monthly, and annual kilowatt-hour energy consumption, accounting for weekly schedules and cycling compressor behavior.
Daily_kWh = (Watts × Hours_Per_Day × (Days_Per_Week / 7) × Duty_Cycle) / 1,000Variable Definitions
WattsAppliance Running Wattage(W)- Nominal power draw under active operation (Volts × Amps × Power Factor).
Hours_Per_DayDaily Operating Time(hours)- Active hours of use per operating day.
Days_Per_WeekWeekly Schedule(days/week)- Number of operating days per 7-day calendar week.
Duty_CycleCompressor / Heating Duty Cycle(fraction)- Fraction of time the appliance draws active power while turned on (e.g. 33% for refrigerators).
Engineering Notes & Standards
- Monthly kWh is derived using exact Gregorian calendar normalization: Daily_kWh × 30.4375 (365.25 ÷ 12).
- Annual kWh = Daily_kWh × 365.25.
Frequently Asked Questions (FAQ)
How do I calculate an appliance's electricity usage in kWh?
Which home appliances use the most electricity?
How much electricity does an average home use per month?
What is an appliance duty cycle?
How much electricity does your home use?
Build a list of appliances using our interactive builder above to calculate total daily, monthly and annual consumption. You can link this daily load directly into our Battery Size Calculator or Solar Panel Size Calculator.
Improve estimate accuracy
Replace presets with measured or nameplate values and your actual usage schedule. Cycling loads such as refrigerators can be represented with a duty cycle. Read the methodology and sources for the calculation approach and limitations.