Electricity Cost Calculator

How to use

1. 1Pick your currency and either keep the sample tariff or type your own cost per kWh from your latest electricity bill.
2. 2Switch the power input between Watts and Kilowatts, then enter the wattage from the device label, spec sheet, or a smart-plug reading.
3. 3Set the hours per day the device is on (use 24 for always-on devices like a fridge) and the days per week if it is not used every day.
4. 4Read the running cost cards for hour, day, week, month, and year, plus the matching kWh totals and the estimated annual CO2.
5. 5Use a Quick-fill appliance chip to load a typical wattage and daily-use time, copy any single value, or use Copy full report to grab the whole breakdown.

About this tool

Electricity Cost Calculator turns an appliance's wattage and how often you use it into a real running cost in your currency. Enter the device power in watts or kilowatts, the hours per day in use, the days per week in use, and your tariff per kWh, and the calculator returns the cost per hour, per day, per week, per month, and per year, alongside the matching kWh totals so you can sanity-check the math against your utility bill. The numbers come from the textbook formula: power in kilowatts equals watts divided by 1000, daily energy is power times hours per day, weekly energy is daily energy times days per week, monthly energy uses an average of 4.348 weeks per month, and yearly energy uses 52.143 weeks per year. Cost is the energy total times your unit rate. A second readout estimates the annual CO2 footprint by multiplying yearly kWh by a grid carbon intensity in kilograms of CO2e per kWh; the default of 0.42 kg per kWh is close to the IEA's reported worldwide average for recent years and is presented as an estimate that you should override with a value for your country, supplier, or 100 percent renewable mix when accuracy matters. A library of more than thirty common-appliance presets fills in realistic mid-range wattages and typical daily usage in one click, including LED and incandescent bulbs, refrigerators, freezers, microwaves, kettles, dishwashers, washing machines, dryers, irons, vacuums, window and central air conditioners, space heaters, electric ovens, water heaters, gaming PCs, game consoles, EV Level 2 chargers, and Wi-Fi routers, so you can quickly compare which devices dominate the bill. A Working panel shows every step (kW, daily kWh, weekly kWh, yearly kWh, yearly cost) so you can audit the result, copy any single value, or copy the full report. Useful for homeowners and renters trying to forecast a power bill, off-grid and solar planners sizing a battery bank, students answering an energy homework problem, gamers and crypto enthusiasts estimating cost-per-hour of running rigs, EV drivers comparing charging costs, and anyone deciding whether an old freezer or AC is worth replacing with a more efficient model. Everything runs locally in your browser, so the wattages, hours, and tariffs you punch in for budgeting or shop-floor calculations never leave your device.

Free to use. Works in your browser. No signup, no login.