Energy Cost Calculator
Work out what any electrical appliance costs you to run. Enter its power consumption in watts (W) or kilowatts (kW), how many hours per day you use it, and your electricity price per kilowatt-hour (kWh) — in cents, pence, rupees or pesos — and press Calculate to get the energy consumed per day in kWh plus the cost per day, per month and per year. Everything runs locally in your browser.
Pick country and appliance (optional)
The country and typical-appliance dropdowns are there for orientation. They do not change the math: type your own power consumption and electricity price so the result matches your actual tariff and device.
Enter power, hours and price
Type the power consumption and choose watts (W) or kilowatts (kW) — 1 kW = 1000 W. Enter the hours of use per day (up to 24 for devices left on continuously), then the price of 1 kWh in your billing unit: cent, pence, rupee or peso.
Press Calculate, read day / month / year
You get the energy consumed per day in kWh and the cost per day, month (30 days) and year (365 days), shown in your major currency unit (dollars, pounds, rupees, pesos). Copy any value to your clipboard or press Reset to start over.
How to calculate energy cost
- How do you calculate energy consumption in kWh per day?
- The energy E in kilowatt-hours (kWh) per day is equal to the power P in watts (W) times the number of usage hours per day t, divided by 1000 watts per kilowatt: E(kWh/day) = P(W) × t(h/day) / 1000. For kW input, E(kWh/day) = P(kW) × t(h/day).
- How do you calculate the energy cost per day?
- The cost per day is equal to the energy E in kWh per day times the cost of 1 kWh in cents per kWh, divided by 100 cents per dollar: Cost(/day) = E(kWh/day) × Cost(cent/kWh) / 100. The same division by 100 converts pence to pounds, rupee paise-style minor units to rupees, and centavos to pesos.
- How are the monthly and yearly costs computed?
- Month = daily cost × 30 days and year = daily cost × 365 days, assuming the same usage every day. Real bills vary with season and tariff tiers, so treat month/year as estimates for the same daily pattern.
- Worked example
- A 1000 W air conditioner used 8 hours per day at 12 cents per kWh: E = 1000 × 8 / 1000 = 8 kWh/day; cost/day = 8 × 12 / 100 = $0.96; cost/month = 0.96 × 30 = $28.80; cost/year = 0.96 × 365 = $350.40.
- What wattage do common appliances use?
- Typical orders of magnitude: LED television around 60–120 W, desktop computer around 200 W, laptop around 50–100 W, refrigerator compressor averaged over the day around 100–150 W, kettle around 2000 W, heater around 1500 W, air conditioner around 1000 W per ton-class unit. Check the nameplate of your own device for its real power draw.
Privacy: every calculation runs in your browser tab — no value you type is sent anywhere. Copy buttons use your clipboard only. Monthly and yearly figures are 30/365-day estimates for a constant daily usage pattern.