What does it cost to run?
Enter an appliance's wattage, how long it runs, and your electricity rate — get the cost per day, month and year. Or build a whole-home list and see which appliance is quietly running up the bill. The maths is one line: kWh = watts × hours ÷ 1,000, then kWh × your rate.
The $0.17/kWh default is a rough example rate — about the US residential average on EIA figures, and it moves over time. Type in the rate from your own electricity bill for numbers that mean anything for your home. Wattages below are typical values or ranges for common models. Your appliance’s nameplate or manual is the authority — check it and edit the number.
Cost of one appliance
Presets fill in a typical wattage and schedule — both stay editable.
Whole-home list: find the expensive appliances
Add a row per appliance. The list totals your estimated monthly electricity use, and the ranking underneath sorts everything by monthly cost so the biggest loads surface first — in most homes that is heating, cooling and hot water, not the phone charger.
Biggest loads first
| Appliance | Watts | kWh / month | Cost / month | Share |
|---|
This is a model of the appliances you list, not your whole meter — lighting circuits, cooking and anything you leave off won't appear. Compare the kWh total with a real bill to see how much of your use the list explains.
Time-of-use rates: peak vs off-peak
On a time-of-use plan the same appliance costs different amounts at different hours. Put the load in, split its running time between the peak and off-peak windows, and compare with a flat rate. Shifting a dishwasher, dryer or EV charge out of the peak window is usually the cheapest "efficiency upgrade" there is.
| Window | kWh / month | Cost / month |
|---|---|---|
| Peak | 120 | $36.00 |
| Off-peak | 360 | $36.00 |
| Time-of-use total | 480 | $72.00 |
| Same use on the flat rate | 480 | $81.60 |
With the starting numbers, the split schedule costs $72.00 against $81.60 flat — the peak hours are few but priced at nearly double.
A worked example, start to finish
A 100 W bulb (or a small fan, or an old games console actually being played) running 10 hours a day: 100 × 10 ÷ 1,000 = 1 kWh a day, 30.0 kWh over a 30-day month, and 30.0 × $0.17 = $5.10 a month. Nothing in the calculator does more than that one line of arithmetic — which is the point: once you can run it for one appliance, you can run it for anything with a wattage on the label.
Scale changes the story fast. A 3,500 W central air conditioner running 8 hours a day uses 840 kWh a month — about $142.80 at the same rate. Two appliances, same formula, a 28× difference in the bill. That is why the whole-home list above sorts by cost: the top two or three rows are almost always where the money is.
The loads you never switch on
Some devices draw power all day while doing nothing — a DVR box idling at 25 W burns about 219 kWh a year, roughly $37 at the example rate, before it records a single show. See the standby power table for the usual suspects and what each one costs per year.
Popular appliances, costed
Full pages for the appliances people ask about most — each with a low / typical / high wattage range and the running cost at each:
- Air conditioner electricity cost
- Space heater electricity cost
- Electric oven electricity cost
- Washing machine electricity cost
- Gaming PC electricity cost
- Refrigerator electricity cost
- Clothes dryer electricity cost
- All appliances on one chart
Questions
- How do I find my electricity rate?
- It is printed on your bill as a price per kWh — sometimes split into a supply and a delivery charge; add the two together. If your plan has time-of-use pricing, use the peak and off-peak rates in the third calculator instead. The $0.17 default here is only a rough US average example.
- Where do I find an appliance's wattage?
- On the nameplate — a sticker or embossed panel, usually on the back or underside — or in the manual. If it lists amps instead, watts ≈ amps × volts (120 V in North America, 230 V in most of Europe). A plug-in energy monitor gives a measured figure if the label is missing.
- Why does my estimate differ from my bill?
- Because real use is messier than a schedule: thermostats cycle compressors off, heaters run less on mild days, and bills add fixed charges, taxes and tiered pricing that a per-kWh estimate doesn't model. Treat the result as a planning figure that tells you which appliances matter, not a prediction of the invoice.
- What uses the most electricity in a typical home?
- Heating and cooling first, then water heating, then big motor and heat appliances — dryer, oven, pool pump. Lighting and electronics are usually small by comparison, which is why the whole-home list sorts by monthly cost instead of by how often you touch the device.
- Does turning things off at the wall actually save money?
- For a handful of always-on loads, yes — a DVR box or an old console in instant-on mode can cost more idling for a year than a efficient bulb costs in use. The standby page puts a yearly figure on each of the common ones.