Simple energy estimate

NAS Power Cost Calculator

Apply measured or vendor-listed power draw to operating hours and your electricity price.

Formula

Watts ÷ 1000 × hours × days = kWh. The calculator multiplies energy by the price you enter.

This is not a utility-bill calculator. Tiered rates, fixed charges, taxes, seasons, and whole-home use vary by location. Use the result to compare the incremental cost of a NAS.

Improve the estimate

Drive sleep and workloads vary. A smart-plug average measured for three to seven days is more useful than a maximum power rating.

Related checks

Compare capacity by drive count and review the hard-drive buying checklist.

Worked examples

Always-on two-bay NAS

At 25 W, 24 hours, 30.4 days, and $0.16/kWh, the estimate is 18.24 kWh and $2.92 per month. Use a low value only when drive sleep is proven reliable.

Always-on four-bay NAS

At 45 W under the same assumptions, the estimate is 32.83 kWh and $5.25 per month. Measure at the wall to include UPS conversion losses.

Home server for 12 hours

At 80 W for 12 hours over 30.4 days, energy is about 29.18 kWh. Weigh scheduled shutdown against missed jobs and extra drive cycles.

Last reviewed: 2026-08-21