PC Electricity Cost Calculator
Estimate your computer’s daily, monthly and annual electricity cost from average wall power, hours of use and your energy tariff. See both kWh and cost.
Monthly electricity cost
Use measured wall power where possible. Annual cost uses 365 days. Currency defaults to USD; change the display symbol below.
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How this calculator works
An electricity tariff charges for energy, not instantaneous power. Multiply average wall power by operating time to find energy in kilowatt-hours. A power supply rated at 750 W does not continuously consume 750 W. Use a wall-meter average across your normal activity instead of the PSU rating.
Formula
kWh = watts × hours / 1,000; cost = kWh × tariff
Assumptions & limitations
Use measured wall power where possible. Annual cost uses 365 days. Currency defaults to USD; change the display symbol below.
Sources & reference material
- Virginia Tech Extension: electricity use ↗
Background for converting appliance watts and operating time into kilowatt-hours.
Worked example
A computer averaging 350 W for 4 hours uses 350 × 4 ÷ 1,000 = 1.4 kWh per day. At $0.20/kWh, that is $0.28 daily, $8.40 for a 30-day month and $102.20 over 365 days. Fixed utility charges are not part of this incremental cost.
If power use changes substantially between active and idle hours, use the Gaming PC Electricity Cost Calculator to calculate each state separately.
Our approach to calculations ↗Common questions
Should I enter my PSU rating?
Use average power measured at the wall. A 750 W power supply rating describes capacity, not continuous energy consumption.
Is the monitor included?
Only if its power is included in your entered wattage. Add monitor and peripheral demand if you want the cost of the entire setup.
Why is annual cost different from monthly cost times twelve?
Annual cost uses 365 days. Monthly cost uses your selected month length, so multiplying that month by twelve can represent a different number of days.