Calculate your cost
Start with the example below, then replace the wattage, daily runtime, and rate with the numbers for your desktop computer.
This setup uses about 48 kWh in a 30-day month.
Please enter valid values within the ranges shown.
| Schedule | Hours/day | Cost/month |
|---|---|---|
| Half runtime | 4 | $4.52 |
| Page example | 8 | $9.04 |
| Longer runtime | 12 | $13.56 |
Same 200-watt input and 18.83¢/kWh rate; only runtime changes.
Formula for the page example
0.2 kW × 8 hr × $0.1883 = $0.30 per day
Convert watts to kilowatts, multiply by the active hours used each day, then multiply by the electricity price in dollars per kWh. Multiply the daily result by 30 for the monthly estimate shown above.
How to read this estimate
A general-purpose desktop spends much of a typical workday below peak power. Its workload, monitor, and sleep settings determine the actual total, so an all-day estimate should include idle and sleep time.
Use this as a baseline until you can check the label or measure the desktop computer directly. Model, settings, condition, climate, and household routine can all change the result.
What changes the cost?
- 01
Processor workload, graphics hardware, and connected storage
- 02
Number, size, and brightness of monitors
- 03
Active hours, idle time, sleep settings, and power-supply efficiency
Ways to spend less
- Enable automatic display-off and system sleep.
- Disconnect unused external drives and accessories.
- Measure at the wall if the machine runs intensive tasks for long periods.