Ever wonder how much it costs to run your air conditioner, space heater, or gaming PC? This electricity cost calculator converts watts and hours into actual dollar costs using your local electricity rate. The average US electricity rate is $0.16/kWh, but rates vary from $0.10 (Louisiana) to $0.36 (Hawaii). Knowing your per-appliance costs helps you cut your electricity bill strategically.
The biggest electricity consumers in a typical home: central air conditioning (3,500W, ~
A common misunderstanding: wattage listed on an appliance is maximum power draw, not constant. A 1,500W space heater with a thermostat cycles on and off, averaging perhaps 900W. A refrigerator rated 150W only runs its compressor about 40% of the time, effectively using 60W on average.
LED lighting has dramatically reduced lighting costs. Replacing one 60W incandescent bulb with a 9W LED saves about $8/year per bulb. A house with 30 bulbs saves $240/year — the LEDs pay for themselves in months.
Reach for this calculator when precision matters more than rough approximation — whether that is for a financial decision, a planning task, or simply getting the right answer the first time.
The most frequent error is using approximate inputs in a precise calculation and treating the result as if it were exact. The output is only as accurate as the inputs — imprecise measurements or estimated values produce imprecise results.
A student planning their revision schedule uses the calculator to distribute a fixed number of study hours across multiple subjects based on weighting, ensuring the time allocation matches the importance of each topic in the final assessment.
Electricity Cost Formula
Cost = (Watts × Hours ÷ 1000) × Price per kWh
Watts ÷ 1000 converts to kilowatts. Kilowatts × Hours = kWh (kilowatt-hours), the unit on your electricity bill. Multiply by your rate to get cost.
A 1,500W space heater running 8 hours/day at $0.16/kWh.
Result: Daily:
A modern 55-inch LED TV uses about 60-90W. At $0.16/kWh and 5 hours/day:
A desktop PC uses 200-500W under load, 60-100W idle. A laptop uses 30-65W. A gaming PC with a high-end GPU can hit 500-800W during gaming. At 5 hours/day, a gaming PC costs
A kWh is 1,000 watts used for 1 hour. A 100W bulb running 10 hours = 1 kWh. It's the standard billing unit for electricity. The average US home uses about 886 kWh/month.
Top savings: switch to LED bulbs ($240/year), use a programmable thermostat (10-15% heating/cooling savings), run dishwasher/laundry during off-peak hours, and eliminate phantom loads with smart power strips (
A central AC unit (3,500W) running 8 hours/day costs
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