Appliance Running Cost Calculator

To find an appliance's running cost over a period, multiply its kilowatts by hours per day by the number of days, then by your rate. A 150 W appliance running 24 hours a day for 30 days uses 108 kWh. At $0.17/kWh that is $18.36 for the month, about $0.61 a day and roughly $223 a year. The calculator above returns all of these instantly once you enter your own rate.

This tool differs from a simple daily calculator by adding a days input, so you can price a full billing cycle, a week-long trip, or a 90-day heating season in one calculation. Because the electricity rate is yours — taken from your bill rather than a national average — the period cost is genuinely actionable rather than a rough guess.

The equation extends the basic cost formula with a days term so it spans any window:

The middle of the equation, (Watts ÷ 1000) × Hours × Days, is total energy in kilowatt-hours — the exact quantity your meter counts and your utility charges for. Multiplying that energy by your rate converts it to dollars. Working an example step by step:

• Power to kilowatts: 150 W ÷ 1000 = 0.15 kW.
• Daily energy: 0.15 kW × 24 h = 3.6 kWh per day.
• Period energy: 3.6 kWh × 30 days = 108 kWh.
• Cost: 108 kWh × $0.17 = $18.36.

Set days to match your question: 7 for a week, 30 or 31 for a month, 90 for a season, 365 for a year. If your appliance is rated in amps rather than watts, convert with the AC amps to watts calculator first. To compare several appliances side by side, the power consumption calculator aggregates a whole household.

Each example shows the arithmetic so you can reproduce it for your own appliance.

Example 1 — Refrigerator for a month. A modern fridge draws about 150 W and its compressor cycles roughly 8 hours' worth per day. Energy = 0.15 × 8 × 30 = 36 kWh. Cost = 36 × 0.17 = $6.12 a month, about $74 a year. If you instead assume 24 h of continuous draw you would triple the estimate — which is why realistic run-time matters.

Example 2 — Pool pump over a summer. A 1,200 W pump running 8 hours a day for 90 summer days: energy = 1.2 × 8 × 90 = 864 kWh. Cost = 864 × 0.17 = $146.88 for the season. Cutting the pump to 5 hours a day drops it to $91.80 — a $55 saving from one schedule change.

Example 3 — Electric water heater for a month. A 4,500 W element that actually heats for about 3 hours a day: energy = 4.5 × 3 × 30 = 405 kWh. Cost = 405 × 0.17 = $68.85 a month, roughly $826 a year — typically one of the two or three largest line items in an all-electric home.

Example 4 — A dehumidifier over a damp week. A 500 W unit running 12 hours a day for 7 days: energy = 0.5 × 12 × 7 = 42 kWh. Cost = 42 × 0.17 = $7.14 for the week.

Generic "average cost to run a fridge" articles are wrong for most homes because two inputs — your electricity rate and your appliance's real duty cycle — vary enormously. This calculator asks for both instead of assuming them.

The rate. Enter your blended rate (total bill ÷ kWh used). A household in Washington at $0.11/kWh and one in California at $0.31/kWh will see a nearly 3× difference in the same appliance's cost. No single published figure can serve both.

The hours. An appliance's plate wattage is its maximum draw, not its average. Refrigerators, freezers, air conditioners, and heaters are thermostatically controlled: they switch on and off to hold a temperature. The honest way to model them is "equivalent full-power hours" — a fridge that is plugged in 24 hours but whose compressor runs a third of the time is best entered as 8 hours a day. Getting this right is the difference between a $6 and an $18 monthly estimate.

Because you supply both numbers, the output is specific to your appliance in your home on your utility. That is something no static average — and no AI answer that cannot see your bill — can replicate. For a device you run every day, cross-check the annual figure here against the electricity cost calculator.

The trickiest input is hours per day for cycling appliances. Here is how to estimate the equivalent full-power run-time for common device types so your cost lands close to reality.

• Refrigerators and freezers: roughly a 30–45% duty cycle, so enter 7–11 hours a day for a "24-hour" appliance. Newer inverter compressors run longer at lower power; a mid-range figure of 8 hours works well.
• Window and central air conditioning: highly weather-dependent. On a hot day a unit may run 60–80% of the time (14–19 h equivalent); in mild weather far less. Model peak months separately.
• Space and baseboard heaters with thermostats: often 40–70% duty in cold weather. A "6 hours on" evening might be 3–4 equivalent full-power hours.
• Water heaters: typically 2–4 hours of element time a day for a family, spiking with hot-water demand.
• Resistive, always-fixed loads (incandescent lights, resistive cooktops while in use, hair dryers): enter actual on-time; there is no cycling.

When unsure, a plug-in energy monitor measures actual kWh over a few days and removes the guesswork entirely — then you can back out the true equivalent hours and enter them here.

1. Enter appliance power in watts. Read it from the nameplate or convert from amps (Amps × Volts) if needed.
2. Enter equivalent hours per day. Use real on-time or the equivalent full-power hours from the duty-cycle guide above.
3. Enter the number of days. 7 for a week, 30 for a month, 90 for a season, 365 for a full year.
4. Enter your electricity rate. Divide your latest bill total by the kWh used for a true blended rate.
5. Read the outputs. Period cost is primary; you also get total kWh used, cost per day, and an annualized cost per year.

To compare two appliances — say, keeping an old fridge versus buying a new one — run each and subtract the yearly costs. The gap is your annual saving, which you can weigh against the purchase price.

Pricing appliances one at a time lets you assemble a bottom-up estimate of your electricity bill that you can compare against the real statement. Add up the monthly cost of your handful of biggest loads — heating or cooling, water heater, refrigerator, dryer, and any pumps — and you will typically capture 70–80% of a home's usage. The remainder is lighting, electronics, and small kitchen appliances.

This bottom-up approach exposes where the money is. In many homes the top three loads dwarf everything else, so effort spent trimming a $70/month water heater (lower the thermostat, add a timer, insulate the tank) beats fussing over a $2/month LED bulb. It also flags anomalies: if your appliance budget comes to $110 but your bill is $190, the gap points to something you missed — a well pump, a hot tub, an EV charger, or an underestimated AC duty cycle.

Once your device-level budget lines up with reality, add fixed charges and taxes and you can predict a bill before it arrives. For that final step — including the utility's fixed monthly service charge — move to the electricity bill calculator, and to convert raw kilowatt-hours to dollars for any block of energy use the kWh cost calculator.

Running cost over a period is the foundation of a smart purchase decision, because the sticker price of an appliance is often a small part of what it truly costs you. A cheap appliance that runs constantly can cost more over its life than an efficient one that costs more up front.

Consider two refrigerators: an old unit drawing an effective 150 W (about 438 kWh a year, roughly $74 at $0.17/kWh) versus a modern ENERGY STAR model at an effective 60 W (about 175 kWh a year, roughly $30). The new fridge saves about $44 a year. Over a 15-year life that is $660 in avoided electricity — often more than the price difference at purchase. Run each appliance through this calculator with its wattage and typical hours, set days to 365, and read the yearly cost to make the comparison in dollars.

The same logic applies to dehumidifiers, pool pumps, well pumps, and window air conditioners — any device that runs long hours. Multiply the annual cost by the expected years of ownership to get a lifetime energy cost, then add the purchase price for a true total cost of ownership. This is how utilities and efficiency programs justify rebates, and you can do the same arithmetic yourself with the numbers this tool provides. For the full-bill context, continue to the electricity bill calculator.

• Treating "always on" as 24 full-power hours. Thermostatic appliances cycle; use equivalent hours, not clock hours.
• Using 31 or 28 days inconsistently. Pick a standard 30-day month for comparisons, or match the exact days in your billing cycle for reconciliation.
• Ignoring seasonality. A heater or AC costs nothing for half the year; annualize on the days actually used, not 365.
• Entering the generation-only rate. Delivery and taxes can add 30–50%; use the all-in blended rate.
• Double-counting. If you already include a device in a whole-home tally, do not add it again in a separate budget line.

Get the hours and rate right and this calculator will predict an appliance's contribution to your bill within a dollar or two.