Your electricity bill doubled but you have no idea which appliance is responsible. Enter wattage, daily hours and your rate to see exactly how many kWh and dollars each device costs you per day, month and year.
How much does a 100 watt appliance cost to run per month?
Your electricity bill doubled but you have no idea which appliance is responsible. Enter wattage, daily hours and your rate to see exactly how many kWh and dollars each device costs you per day, month and year.
A 100 watt appliance running 8 hours per day consumes 100 watts of power every hour it operates. At the US average rate of $0.15/kWh, that translates to a specific monthly cost that depends on how many days you use it. Enter your actual wattage, hours and rate below to see the exact breakdown - daily, monthly and yearly.
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Your electricity bill doubled - but which appliance is responsible?
The solution: calculate each appliance individually
How to use the electricity usage calculator - step by step
- Appliance wattage (W) - check the label on the back or bottom of the device. Common values: fridge 100-200W, washer 1,500-2,500W, TV 50-200W, PC 200-500W, space heater 1,000-2,000W.
- Hours per day - how long the device actually runs. A fridge compressor cycles on/off and effectively runs about 8-12 hours. A TV might run 4-6 hours. A space heater: 6-10 hours in winter.
- Electricity rate ($/kWh) - find this on your utility bill. US average: $0.12-0.16. UK: $0.28-0.34. EU: $0.20-0.35. California/Hawaii: $0.25-0.40.
- Days used per month - a fridge runs every day (30). A washing machine might run 8-12 days. A space heater only during cold months (maybe 20 days).
- Read the result - three tiles show daily, monthly and yearly consumption in kWh and dollars. The formula tile shows the math so you can verify.
What common appliances really cost per month
All costs at $0.15/kWh (US average). Your rate may differ - adjust the calculator accordingly.
| Appliance | Watts | Hours/day | kWh/month | Cost/month |
|---|---|---|---|---|
| Refrigerator | 150 | 24 (compressor ~10) | 36 | $5.40 |
| Washing machine | 2,000 | 1 (10 days/mo) | 20 | $3.00 |
| Desktop PC | 300 | 8 | 72 | $10.80 |
| Gaming PC | 500 | 6 | 90 | $13.50 |
| TV (55 inch LED) | 100 | 5 | 15 | $2.25 |
| Space heater | 1,500 | 8 | 360 | $54.00 |
| Air conditioner (window) | 1,200 | 10 | 360 | $54.00 |
| Electric oven | 2,500 | 1 (15 days/mo) | 37.5 | $5.63 |
| Dishwasher | 1,800 | 1.5 (20 days/mo) | 54 | $8.10 |
| LED light bulb | 10 | 6 | 1.8 | $0.27 |
Decision table: where to cut first
| If your bill spiked because of... | What to do | Savings/month |
|---|---|---|
| Space heater (8 h/day) | Use a timer, insulate room, lower thermostat | $20-30 |
| AC running 10+ hours | Set to 25-26C, use ceiling fans, seal windows | $15-25 |
| Gaming PC left on 24/7 | Enable sleep mode, turn off when not gaming | $8-15 |
| Old fridge in garage | Replace with Energy Star model or unplug | $5-15 |
| Incandescent bulbs (10x 60W) | Switch to LED (10W each) - same brightness | $4-8 |
Practical examples
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Calculator verified by the LiczGrupa.pl team
Content, formulas and results have been reviewed for accuracy and relevance by our team of specialists.
Reviewed by: Patryk Matyjasik