How it's calculated
Daily kWh = (watts ÷ 1000) × hours per day × quantity. This converts power (watts) to energy (kilowatt-hours).
Daily cost = daily kWh × rate per kWh. Monthly cost uses 30 days; yearly cost uses 365 days.
Lifestyle & Everyday
Electricity Cost Calculator
Find out how much any appliance costs to run — per day, month, and year.
Calculator
Monthly cost
$13.50/ month
$164.25 per year
Daily cost
$0.45
Monthly cost
$13.50
Yearly cost
$164.25
kWh / month
90
Trim the runtime
$54.75Using it 1 hour less per day would save about $54.75 per year.
Uses a 30-day month for monthly estimates. Your actual bill may vary by tariff, taxes, and usage patterns.
Where do I find my appliance's wattage?
Check the label on the back or bottom of the device, the product manual, or the manufacturer's website. Many appliances also list watts on the power cord.
Where do I find my electricity rate?
Look at your electricity bill — the rate is usually shown as a price per kilowatt-hour (kWh). Rates vary widely by country and utility provider.
Why does the calculator use 30-day months?
Using 30 days per month makes monthly and yearly estimates consistent and easy to compare. Your actual bill will reflect the real number of days in each month.
About this calculator
This calculator tells you how much a device or appliance costs to run — per day, per month, and per year. Enter the power draw in watts, how many hours a day it operates, how many units you have, and your local electricity rate. The result updates instantly so you can spot the biggest energy consumers in your home or office.
How to read your results
The three headline figures are the daily, monthly (30-day), and yearly (365-day) running costs. A kilowatt-hour (kWh) is the standard billing unit: one kWh is the energy used by a 1,000-watt device running for one hour. Your bill converts kWh into a money amount using your tariff rate. Note that electricity rates vary widely by country, region, and time-of-use tariff — some utilities charge more during peak hours — so use the exact rate from your most recent bill for the closest estimate.
Worked example
A 1,000-watt microwave runs 3 hours per day, quantity 1, at a rate of 0.15 per kWh.
Daily energy use is 3 kWh (1,000 W ÷ 1,000 × 3 h). Daily cost is 0.45, monthly cost is 13.50 (0.45 × 30), and yearly cost is 164.25 (0.45 × 365).
Frequently asked questions
Where do I find the wattage of my appliance?
Check the label on the back or bottom of the device, the product manual, or the manufacturer's website. Most appliances list a rated wattage. If a range is given (e.g. 600–1,200 W), use the average or the setting you most often use.
Where do I find my electricity rate?
Look at your electricity bill — the rate is usually shown as a price per kilowatt-hour (kWh). If your utility uses a tiered or time-of-use tariff, use the tier that applies to the hours you run the appliance.
Why does the calculator use a 30-day month?
A fixed 30-day month keeps monthly and yearly estimates consistent and comparable across all periods. The yearly figure always equals the daily cost multiplied by 365.
Can I calculate the cost for multiple identical devices?
Yes — set the quantity field to the number of identical devices. The calculator multiplies the energy use and cost by that count before displaying results.
Does standby or idle power count?
Standby power is real but typically small (often 1–5 W per device). You can add a second calculation with the standby wattage and the hours the device is plugged in but not actively used to get a more complete picture.
How it's calculated
Energy consumed per day (across all units) equals power in kilowatts multiplied by hours of use multiplied by quantity: daily kWh = (watts ÷ 1,000) × hours per day × quantity. Running cost then follows directly: daily cost = daily kWh × rate per kWh. Monthly cost = daily cost × 30. Yearly cost = daily cost × 365.
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