π° Appliance Electricity Cost Calculator
What any device costs to run: per day, month, and year.
Running Cost
How to Use the Electricity Cost Calculator
Enter the appliance wattage (nameplate or measured), hours it runs daily, and your electricity rate, then press Calculate. You get cost per day, month, and year plus kWh consumed. Find wattage on the device label, in the manual, or with a $20 plug-in meter for the true number including cycling.
Use your all-in rate from the bill: total dollars divided by total kWh, which includes delivery charges and fees. The advertised supply rate understates reality by 30-50% in many areas. Time-of-use customers should use the rate for the hours the device actually runs.
The Formula
A kilowatt-hour is simply 1,000 watts for one hour: the utility billing unit. Everything else is multiplication. The formula assumes steady draw; cycling appliances like fridges average well below nameplate, so measure or derate them (a fridge rated 150W might average 50W).
Worked Example
A 1,500W space heater, 8 hours daily, at $0.17/kWh. Daily kWh: 1,500 Γ 8 Γ· 1,000 = 12 kWh. Daily cost: 12 Γ 0.17 = $2.04. Monthly: $62. Yearly if run all year: $745. That single heater can exceed the rest of the house combined, which reframes every "just run the space heater" decision.
What Things Actually Cost
At $0.17/kWh: LED bulb (10W, 5h) costs 0.85Β’/day. Big TV (200W, 4h): 13.6Β’/day. Gaming PC (400W, 3h): 20Β’/day. Clothes dryer (3,000W, 1h): 51Β’/load. Central AC (3,500W, 8h): $4.76/day. Electric water heater share: ~$1.50/day. The pattern is clear: heat and motors dominate; electronics sip.
Annualize the surprises: a garage fridge from 1995 can cost $150+/year; a pool pump $400-600; an always-on old plasma TV $100. The calculator turns vague guilt about usage into ranked targets. Attack the top of the list first; unplugging phone chargers is theater by comparison.
Cutting the Big Loads
Heating and cooling are half the bill. A heat pump delivers 2-4x the heat per kWh of resistance heat; proper insulation and air sealing cut the load itself. Programmable setbacks (7-10Β°F for 8 hours) save ~10% yearly. Water heating: lower the tank to 120Β°F, insulate it, and fix dripping hot taps.
Laundry: wash cold (90% of washer energy is heating water) and use the dryer moisture sensor instead of timed dry. Dishwasher: skip heated dry. These are free behavioral changes worth hundreds yearly. Then consider hardware: heat-pump dryer, variable-speed pool pump, smart thermostat.
Vampire Loads and Standby
Devices draw power doing nothing: cable boxes (15-30W), game consoles in instant-on (10-15W), old stereos, and anything with a warm transformer. A home typically wastes 50-100W continuously, $75-150/year. Smart strips cut peripherals with the main device; advanced ones sense current and kill standby automatically.
Measure before unplugging everything: a modern phone charger idling draws under 0.5W, about 75Β’/year. Focus on the entertainment center and home office, where a dozen devices idle together. One smart strip there beats a year of charger-unplugging theater.
Reading Your Bill
Bills bury the rate in line items: supply (generation), delivery (poles and wires), and fixed fees. Your marginal kWh costs supply + delivery; the fixed fee does not change with usage. Divide (total β fixed fees) by kWh for the rate to use in decisions like "should I run the dryer now."
Time-of-use plans flip the math: peak rates can double off-peak. Shifting laundry, dishwashing, and EV charging to off-peak hours cuts those loads cost 30-50% with zero lifestyle change. If your utility offers it and you can shift loads, TOU usually wins.
EV Charging Costs
An EV driven 1,000 miles/month at 3.5 miles/kWh uses ~286 kWh, about $49 at average rates versus $130+ in gasoline for a 30 MPG car. Home charging on off-peak rates can halve that again. Public fast charging costs 2-4x home rates, so road trips budget differently than daily driving.
Size the circuit honestly: a Level 2 charger at 7.7 kW adds serious load, and panel capacity matters. But the per-mile math is overwhelmingly favorable; fuel savings alone often cover the charger installation within a couple of years for average drivers.
Solar and Net Metering
Rooftop solar changes the rate question entirely: daytime loads run on sunshine, and net metering credits surplus. Size the system to your measured usage (the calculator helps inventory it), not to rules of thumb. Payback runs 6-10 years in most US markets at current rates.
Batteries add resilience more than savings under most rate structures; the math works where outages are frequent or utilities pay little for exported power. As with everything electric, measure first, then decide.
A Second Worked Example: The Home Office
Add up a typical remote-work setup at $0.17/kWh. Laptop (65W) plus monitor (25W) plus desk lamp (10W) is 100W, running 9 hours a day: 100 times 9 divided by 1,000 is 0.9 kWh, or about 15 cents a day. A second monitor adds 25W, another 4 cents. Over a 22-day work month, the whole setup costs roughly $3.30-4.20. The computer is not the energy story in a home office. The heating or cooling keeping you comfortable while you work is, often 10-20x the electronics.
Run the same math for a gaming rig: 500W PC plus 200W TV, 3 hours a night. That is 700 times 3 divided by 1,000, or 2.1 kWh, about 36 cents a day, roughly $10.80 a month. Two very different setups, same formula, and now you know which line on the bill to blame.
Rate Plans Compared: Flat, Time-of-Use, and Tiered
Flat-rate plans charge one price per kWh all day. Simple, predictable, and usually not the cheapest if your utility offers options. Time-of-use plans split the day: cheap overnight, expensive late afternoon and early evening when the grid peaks. If you can shift big loads, laundry, dishwasher, EV charging, to off-peak hours, time-of-use can cut 10-20 percent off the bill. If you run the AC hardest at 6 PM, it can cost you more.
Tiered plans charge more per kWh as your monthly usage climbs into higher tiers. The first few hundred kWh are cheap. Past that, each kWh costs more. On a tiered plan, cutting usage pays twice: you use fewer kWh and the ones you still use may drop into a cheaper tier. Check your bill for which plan you are on before optimizing. The same appliance costs a different amount under each structure.
Mistakes That Skew Your Estimate
The most common is using the supply rate instead of the all-in rate. Utilities advertise the generation price, but delivery charges, fees, and taxes ride along on every kWh. Divide total bill dollars by total kWh for the real number. It is routinely 30-50 percent higher than the headline rate. Second is trusting nameplate wattage for cycling appliances: a 150W fridge averages far less because the compressor cycles off, while a 1,500W space heater draws the full 1,500 the whole time it runs.
Third is forgetting duty cycle on anything with a thermostat: water heaters, ovens, and AC units do not draw nameplate power continuously. A 4,500W water heater that runs 3 hours a day costs less than a 1,500W heater running 12 hours. Hours at full draw is the number that matters, not the wattage on the label. When in doubt, a plug-in meter for a week beats a label reading every time.
Frequently Asked Questions
How do I calculate electricity cost?
Multiply watts Γ hours used Γ· 1000 to get kWh, then multiply by your rate per kWh. A 100W bulb for 5 hours is 0.5 kWh; at $0.17/kWh that costs 8.5 cents. The calculator runs this for any appliance. Cycling appliances like fridges average well below nameplate, so measure with a plug meter for truth.
How much does it cost to run a space heater?
A 1,500W heater running 8 hours uses 12 kWh. At the US average $0.17/kWh, that is $2.04 per day or about $61 per month. Heating with electricity gets expensive fast, which is why heat pumps matter. A heat pump delivers the same warmth for one-third the electricity; the math favors upgrading fast.
What uses the most electricity in a home?
Heating and cooling top the list (about half of home energy), then water heating, then large appliances like dryers and ovens. Electronics and lighting are small by comparison. Attack the big loads first for real savings. Rank your own loads with the calculator above; the top two usually dominate the bill.
How much does a kWh cost in the US?
The national average is around $0.17/kWh in 2026, but it ranges from under $0.10 in some states to over $0.40 in Hawaii and parts of California. Check your bill for your exact rate including delivery charges. Time-of-use plans can halve off-peak rates, so check when your heavy loads actually run.
Does leaving things plugged in cost money?
Yes, standby power ("vampire load") typically adds 5-10% to home electricity use. TVs, game consoles, and chargers draw watts 24/7. Smart power strips that cut standby draw pay for themselves within a year or two. One smart strip on the entertainment center beats a year of unplugging phone chargers.
How much does it cost to run a pool pump?
A 1.5 HP pump draws about 1,100W; running 8 hours uses 8.8 kWh, about $1.50/day at average rates, or $45/month. Variable-speed pumps cut this dramatically by running slower longer. Running slower for longer hours filters the same water for far less money.
Is it cheaper to leave the AC on all day?
Usually not. The "it works harder to cool down" claim is mostly myth; maintaining temperature all day uses more total energy than cooling before you return. A programmable thermostat with a setback saves 5-15%. Pre-cooling before peak-rate hours start is the smart version of leaving it on.
How do I find my electricity rate?
Look at your utility bill: divide total charges by kWh used for the all-in rate, or find the supply + delivery per-kWh lines. Time-of-use plans charge different rates by hour, so check when your heavy loads run. Your marginal kWh costs supply plus delivery; fixed fees do not change with usage.