Tool
Home Server Power Cost Calculator
A machine that idles at 25 W instead of 8 W costs about $27 more a year at the U.S. average rate — and more than double that in Hawaii. Enter your own numbers and see what the gap comes to.
| Machine A | Machine B | Gap | |
|---|---|---|---|
| kWh per year | — | — | — |
| Cost per year | — | — | — |
| Cost over 3 years | — | — | — |
A range means the source published a range. Both ends are shown; pick the one that matches how you would run the machine.
How this is calculated
watts ÷ 1000 × 24 hours × 365 days × years × rate. The default rate is the U.S. average residential rate, 18.31¢/kWh (EIA, July 2026).State averages ranged from 12.72¢ (Louisiana) to 48.00¢ (Hawaii). Your utility bill lists your rate; use the all-in number if it shows one.
The presets are idle measurements published by third parties, not our own. Each was measured under specific conditions — operating system, add-in cards, power settings — and the same machine can land far from these numbers in a different configuration. The conditions are footnoted in the comparison articles below.
Idle draw is the right number for a machine that runs all day and does something only occasionally. If yours is busy most of the time, load draw matters more, and this tool will understate the bill.