Electricity Cost Calculator
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What Your Result Means
- Daily cost: The estimated electricity cost for running the appliance at the specified wattage and hours per day. Use this to compare the cost of different devices.
- Monthly cost: The daily cost multiplied by 30 days. This is the amount the appliance adds to your monthly electric bill, assuming consistent daily usage.
- Yearly cost: The daily cost multiplied by 365 days. Helpful for evaluating whether upgrading to a more efficient model would pay for itself over a year.
- Monthly kWh: The total energy consumed per month in kilowatt-hours. Your utility bill is priced per kWh, so this figure lets you cross-reference directly with your bill.
How This Calculator Works
You enter the appliance's wattage, the number of hours it runs per day, and your electricity rate in dollars per kilowatt-hour. The tool converts watts to kilowatts (÷ 1,000), multiplies by daily hours to get daily kWh, then multiplies by 30 or 365 for monthly and yearly estimates. It assumes constant wattage and usage — actual consumption may vary with duty cycles, standby power, and seasonal changes. The rate used should be your effective per-kWh rate, which you can find on your utility bill.
Quick Questions
Where do I find my electricity rate?
Check your most recent utility bill. Look for the line item showing cost per kWh — it is typically between $0.10 and $0.30 in the U.S. depending on your state and plan. If your bill has tiered rates, use the highest tier for a conservative estimate or the blended average for a typical one.
How do I find an appliance's wattage?
Check the label on the back or bottom of the appliance, the product manual, or the manufacturer's website. You can also use a plug-in power meter (like a Kill A Watt) to measure actual consumption. Note that nameplate wattage is the maximum — average draw is often lower.
Why is my actual bill different from this estimate?
Your bill includes all appliances, standby power, taxes, delivery charges, and sometimes tiered or time-of-use pricing. This calculator estimates a single appliance at a flat rate, so it gives a component cost rather than a full-bill prediction.
Does this include standby (phantom) power?
Only if you include it in the wattage. Many devices draw 1–5 watts even when "off." To account for standby, add those watts separately or use the device's average consumption instead of its peak wattage.
Sources
- U.S. Energy Information Administration — Electric Power Monthly (average electricity prices by state)
- U.S. Department of Energy — Appliances & Electronics (wattage estimates and energy-saving tips)
- ENERGY STAR (certified appliance efficiency ratings)
Method & review
Estimate only. Results reflect your inputs and standard formulas — they are not financial, tax, legal, health, or investment advice. Verify important decisions with a qualified professional.