Electricity Cost
Daily, monthly and yearly running cost of any electrical appliance.
Monthly cost
$33.75
7.5 kWh/day
Daily cost
$1.13
Yearly cost
$410.63
kWh / month
225
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How the Electricity Cost works
The Electricity Cost Calculator helps homeowners, renters, and small business owners instantly figure out exactly how much any electrical appliance costs to run — per day, per month, and per year — based on its wattage, daily usage, and your local electricity rate.
At its core, this calculator converts an appliance's power draw (measured in watts) into kilowatt-hours (kWh) — the universal billing unit used by every electricity provider worldwide. You supply three inputs: the appliance's wattage (found on its label or in the manual), how many hours per day you use it, and your electricity rate in cents or dollars per kWh. The tool then multiplies these together to produce running costs across daily, monthly, and yearly timeframes, giving you a complete financial picture at a glance.
Your electricity rate is the single biggest variable in the calculation, and it varies dramatically by region. In the United States, the national average sits around 16–17 cents per kWh as of 2024, but rates range from roughly 10 cents in states like Louisiana to over 30 cents in Hawaii and parts of California. In the UK, rates have hovered around 24–28p per kWh in recent years. Always check your latest power bill for the exact rate — and if your utility uses time-of-use pricing, consider using your peak-rate figure for a conservative worst-case estimate.
Wattage ratings on appliances reflect maximum or rated power draw, but actual consumption often differs in practice. A central air conditioner rated at 3,500 W doesn't run at full load continuously; it cycles on and off, effectively averaging a lower consumption. Similarly, devices with standby modes — TVs, gaming consoles, smart speakers — consume power even when 'off.' For the most accurate energy cost estimate, you can use a plug-in energy monitor (like a Kill A Watt meter) to measure real-world wattage rather than relying solely on the nameplate figure.
A common mistake users make is underestimating daily usage hours. A refrigerator, for example, runs 24 hours a day even though its compressor cycles, so entering 24 hours with the average wattage (not peak) gives the most realistic annual electricity cost. Conversely, people often forget to account for seasonal appliances — electric heaters or air conditioners used only 4–5 months a year — which inflates yearly projections if you simply multiply monthly costs by 12. Use the daily and monthly figures for those appliances and multiply by the actual number of months in use for a sharper estimate.
Formula
Cost = (Watts × Hours / 1000) × Rate per kWh
Pro tips
- Check your actual electricity rate on your most recent power bill rather than using a national average — rates vary by up to 3× between US states and even more internationally, so precision here has the biggest impact on accuracy.
- For appliances that cycle on and off (refrigerators, AC units, heat pumps), enter the average running wattage — roughly 30–50% of the peak nameplate wattage — rather than the maximum rating, to avoid overstating your energy cost.
- Run the calculator on your top five energy hogs (typically HVAC, water heater, dryer, refrigerator, and EV charger) first — these usually account for 60–70% of a typical household power bill, so small changes there yield the biggest savings.
- Use the yearly cost output to evaluate appliance upgrades: if a new Energy Star refrigerator saves $80/year in electricity versus your old model, and costs $300 more, it pays for itself in under 4 years — a calculation this tool makes trivial.
- Don't ignore standby consumption. A gaming console drawing 1–2 W in standby 24/7 costs only a few dollars a year, but a poorly designed older TV or cable box drawing 15–20 W on standby can add $20–$30 annually — run those through the calculator to decide if a smart power strip is worth it.
Key terms
- Kilowatt-hour (kWh)
- — The standard unit of electrical energy equal to 1,000 watts consumed for one hour; it is the unit your utility company uses to measure and bill your electricity consumption.
- Wattage
- — The rate at which an appliance consumes electrical power, measured in watts (W); higher wattage means more electricity used per hour of operation.
- Electricity Rate
- — The price your utility charges per kilowatt-hour of electricity consumed, typically expressed in cents per kWh and printed on your monthly power bill.
- Standby Power
- — The small but continuous amount of electricity an appliance draws even when switched off or in sleep mode, sometimes called 'phantom load' or 'vampire power.'
- Running Cost
- — The total electricity cost incurred by operating an appliance over a specific period, calculated from its power consumption and the applicable electricity rate.
- Energy Monitor
- — A plug-in device that measures the actual real-time wattage and cumulative kWh consumption of any appliance plugged into it, enabling more accurate cost calculations than nameplate ratings alone.
