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About Electricity Cost Calculator Online
This tool calculates how much an electrical device costs to run. Enter the device wattage, daily usage hours, and your local electricity rate (in dollars per kWh), and it returns the daily, monthly, and annual cost.
Knowing the cost of running individual devices helps you identify energy hogs and decide which appliances are worth upgrading. An old refrigerator might cost $150/year, while an Energy Star replacement runs $40 — the savings can justify replacement before the old unit fails.
Use it to evaluate space heaters (often very expensive to run), gaming PCs (high wattage × many hours), pool pumps, second refrigerators, server homelabs, and any "always-on" device whose cost adds up over time.
How to use this tool
How to compute the cost of running an appliance
Energy in kWh
"Energy (kWh)" is total consumption — wattage × hours ÷ 1000. A 100W bulb on for 24h uses 100 × 24 / 1000 = 2.4 kWh.
Price per kWh
"Price per kWh" is your utility's rate. Look at your last bill — for tiered/time-of-use plans, pick the band the run would fall under. Currency-agnostic; stay consistent.
Press Run
Result is a single totalCost = kwh × pricePerKwh, rounded to 2 decimals. No fixed connection fees or sales taxes are applied — the output is purely energy * price.
Quick sanity checks
A 1000W heater for 8h/day at $0.20/kWh ≈ $1.60/day ($48/month). An EV charging 30 kWh at $0.13/kWh ≈ $3.90 per full charge. Worth thinking about before letting a space heater run all winter.