Electricity cost calculator

Compare two appliances at the same electricity price

Enter device A above, then device B's watts and daily hours in the comparison. Both use your price per kWh. The annual difference is A minus B: a positive amount means B costs less to run. Purchase price and replacement costs are not included, so this difference alone does not establish whether buying a new device pays off.

Where to find your electricity price

Use the unit rate on your supplier's bill or tariff sheet. If the rate is in cents, divide by 100 before entering it. Include per-kWh charges and taxes you want represented in the result; fixed standing charges are separate. For a variable tariff, enter a representative rate for the hours you actually use the device. There is no automatic price lookup. The displayed currency follows the page language; no currency conversion takes place.

Three examples you can adapt

Illustrative inputs, not measured appliance averages: a 10 W lamp used for 5 hours needs 0.05 kWh/day; a 100 W device used for 3 hours needs 0.3 kWh/day; a 2,000 W heater running at full power for 2 hours needs 4 kWh/day. Multiply each by your unit rate. Use measured average power for devices that cycle on and off rather than assuming their maximum wattage runs continuously.

Watts, kilowatts and kilowatt-hours

Watts (W) describe power: how quickly a device uses energy while running. Divide by 1,000 for kilowatts (kW). Multiply kilowatts by hours to get kilowatt-hours (kWh), the energy you pay for. A 2 kW heater is 2,000 W; enter 2000 in the power field, not 2.

Choose a realistic power and run time

Use a measured average or the power for the operating mode you want to estimate. A label or manual can provide a starting value, but this calculation assumes that power stays constant during the hours you enter. A heater controlled by a thermostat or a cycling refrigerator does not necessarily draw its rated power continuously. A suitable plug-in energy meter can help with devices whose draw varies.

Enter the total hours of actual operation in a day, including fractions: 15 minutes is 0.25 hours. For an always-on device use 24 only if the wattage represents its average across that whole day. The calculator does not model cycling, warm-up, temperature or seasonal changes.

Use your own electricity price

Read the variable price per kWh on your bill or tariff. On this English page, enter dollars per kWh: 30 cents is 0.30, not 30. Include per-kWh delivery charges and taxes if you want them represented. Fixed daily charges or monthly subscriptions are outside the appliance calculation. Changing the site language changes the currency label; it does not convert the price.

The tool does not fetch a live tariff, location or national average. If your rate changes by time of day, calculate each time band separately and add the costs. A single average rate is an estimate; this tool does not schedule usage into cheaper hours.

Worked appliance examples

These are arithmetic scenarios, not measured averages for a product category. At an example price of $0.30/kWh: 100 W for 5 hours uses 0.5 kWh/day and costs $0.15/day, $4.50 per 30-day month and $54.75 per 365-day year. Annual energy is 182.5 kWh.

A 2,000 W heater drawing full power for 2 hours uses 4 kWh/day: $1.20/day, $36.00/month and $438.00/year at the same example price. A 10 W lamp for 5 hours uses 0.05 kWh/day: $0.015/day before rounding, $0.45/month and $5.475/year. Totals are calculated before display rounding, so do not multiply a rounded daily amount to check the yearly figure.

Compare device A with device B

Enter B’s watts and hours in the comparison panel. Both devices use the price above. With A at 100 W for 5 hours and B at 10 W for 5 hours, the annual difference is $49.275 before rounding, displayed as $49.28. That is a difference in running cost under these inputs, not a promise that a replacement will pay for itself. Include purchase and installation costs separately.

Standby and the limits of the totals

Standby is included only when you enter a power and time that represent it. To separate 5 active hours from 19 standby hours, run two scenarios and add their costs. Do not count the same hours twice. A month always means 30 days here and a year 365 days; twelve displayed months therefore cover 360 days, not a whole year.