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.
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.
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.
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.
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.
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.