FigureDesk

Electricity Cost Calculator

Enter an appliance's wattage, how many hours a day you run it, and your electricity rate. FigureDesk shows the energy used and the cost per day, month, and year.

Your numbers

W

Check the appliance's label or datasheet, or use a plug-in power meter for an actual reading.

h
$/kWh

From your utility bill — rates vary widely by location, provider, and time of use.

Result

Cost per day

$1.13

Energy per day
7.5 kWh
Cost per month (30 days)
$33.75
Cost per year (365 days)
$410.63

Given 1500 W, 5 h/day, $0.15/kWh → energy = (1500 / 1000) × 5 = 7.5 kWh/day, cost = 7.5 × $0.15 = $1.125/day

How it works

Electricity is billed by the kilowatt-hour (kWh) — the energy used running a 1,000-watt load for one hour. Multiplying an appliance's wattage by the hours it runs gives the energy used; multiplying that by your rate gives the cost.

energy (kWh/day) = (watts / 1000) × hours/day
cost/day = energy × rate ($/kWh)

Worked example

A 1,500 W space heater run 5 hours a day at $0.15/kWh:

  • Energy: (1500 / 1000) × 5 = 7.5 kWh/day
  • Cost per day: 7.5 × $0.15 = $1.13
  • Cost per month: $33.75
  • Cost per year: $410.63

Important assumptions

  • You supply your own electricity rate — this calculator does not look one up or default to one, since rates vary enormously by location, utility, plan, and time of use. Check a recent bill for your actual $/kWh rate.
  • Assumes constant wattage for the full duration entered — real appliances (especially those with a compressor or heating element) often cycle on and off rather than draw their full rated wattage continuously.
  • Month and year figures are simple extrapolations (30-day month, 365-day year) of the daily figure, not a calendar-accurate billing cycle.

FAQ

How do I find an appliance's wattage?

Check the label or nameplate on the appliance itself, its manual, or the manufacturer's spec sheet. For the most accurate figure, especially for appliances that vary their draw (like a refrigerator or space heater on a thermostat), a plug-in power meter measures actual usage over time.

Where do I find my electricity rate?

Your rate in dollars per kilowatt-hour ($/kWh) is on your utility bill, often listed per tier or time-of-use period. If your plan has multiple rates (e.g., peak and off-peak), run this calculator once per rate for the hours used in each period and add the results.

Why is my actual bill different from this estimate?

Real usage varies day to day, many appliances cycle rather than draw constant power, utility bills often include fixed fees and taxes beyond the per-kWh energy charge, and time-of-use or tiered rate plans charge different amounts depending on when and how much you use — this calculator estimates energy cost alone at a single flat rate.

Does this account for appliances that cycle on and off?

Not directly — enter the appliance's actual average draw or the hours it's actively drawing power, not the total time it's plugged in. A plug-in power meter that reports total kWh over a day is the most reliable way to capture real cycling behavior.

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FigureDesk results are advisory and do not replace a licensed electrician, a qualified engineer, or the applicable local electrical code. Verify any electrical work against your local code and with a qualified professional before relying on it.