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To estimate what a home server or AI workstation costs to run, multiply its average power draw at the wall by the hours it runs, then multiply the resulting kilowatt-hours (kWh) by your electricity rate. The estimate is only as useful as its inputs: use a representative measurement, account for the actual schedule, and include peripherals only if you want their cost included.
Use this formula to estimate electricity cost
Watts measure power at a moment; kilowatt-hours measure energy used over time. One kilowatt is 1,000 watts. The U.S. Energy Information Administration (EIA) explains the relationship between watts and kWh.
- Energy used (kWh) = average watts ÷ 1,000 × hours
- Energy cost = kWh × electricity price per kWh
For a steady device running continuously, a 30-day month has 720 operating hours: monthly kWh = watts ÷ 1,000 × 24 × 30. Use your actual hours if the machine shuts down or sleeps for part of the day.
How much does it cost to run a home server 24/7?
There is no reliable universal cost for a home server or AI workstation: configuration and workload affect its power draw, and the sources cited here do not establish a representative wattage for either category. For a transparent example, a setup averaging 100 W and running 24 hours a day uses 0.1 kW × 24 × 30 = 72 kWh in a 30-day month.
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At 17.30¢ per kWh, that would cost 72 × $0.173 = about $12.46 for the month in energy. At the same illustrative rate, it would use 876 kWh over 365 days and cost about $151.55. The 17.30¢ figure is the EIA’s preliminary 2025 U.S. annual average residential price, reported on a page based on February 2026 Electric Power Monthly data; it is a national reference, not necessarily your rate. Check the EIA’s explanation of electricity prices and factors affecting them.
How to calculate the cost of your own setup
- Choose what to include. Decide whether you are estimating the computer alone or the whole setup. Add the monitor, networking equipment, external storage, or other attached devices only if their energy use belongs in your estimate.
- Measure representative wall power. A reading at the outlet captures the draw of the connected equipment, including power-supply losses. Measure the complete setup if that is the boundary you chose. The U.S. Department of Energy’s worksheet presents a wattmeter as an optional estimation aid (“Optional with wattmeter”). See the DOE worksheet.
- Use an average that reflects your routine. Include ordinary idle and active periods rather than relying on a brief peak. If power changes substantially, estimate idle and active use separately and calculate each interval’s kWh, then add them.
- Convert the average watts to kW. Divide by 1,000.
- Multiply by operating hours. Use the hours in the period you are estimating, such as a day, 30-day month, or year.
- Multiply kWh by your applicable rate. Use the price plan that applies to your household and, where relevant, the time the device runs.
Use your electricity rate, not a generic cost
Electricity prices vary by location, and some utilities offer time-of-day pricing. Use your current utility plan where possible rather than assuming the national average applies. The EIA’s 17.30¢-per-kWh figure is useful for illustrating the arithmetic, but your marginal price may differ. The calculated amount is an estimate of energy charges; the full bill can also include fixed charges, taxes, tiers, credits, or other tariff components.
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For context, the EIA reports that U.S. residential electric-utility customers used an average of 10,791 kWh in 2022, with consumption varying among states. That is a household-level statistic, not an estimate of server or workstation consumption. Read the EIA’s residential electricity-use FAQ.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Why a power supply’s rating is not your electricity use
A power supply’s rated capacity or a component’s advertised maximum does not tell you the system’s average draw during normal use. A wall-side measurement over representative operating periods is more useful for estimating what the equipment takes from the outlet. If you compare two systems, keep the measurement boundary, workload, duration, and electricity rate consistent; compare idle, ordinary work, and sustained compute separately when those states matter to your use.
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