Count the whole day, not only the game
A computer can use different amounts of power while working, idle and asleep. Enter a wall-power reading for each state and the time spent there. The calculator assigns the remaining hours of the day to sleep or off. Active plus idle time must not exceed 24 hours.
A worked example you can change
Assume 250 W for four active hours, 60 W for eight idle hours and 3 W for the remaining twelve hours. These are invented planning inputs, not measurements of a particular model.
| State | Hours | Daily energy |
|---|---|---|
| Active at 250 W | 4 | 1.000 kWh |
| Idle at 60 W | 8 | 0.480 kWh |
| Sleep at 3 W | 12 | 0.036 kWh |
Total: 1.516 kWh per day. At an assumed $0.25/kWh, that is $11.37 over 30 days or $138.34 over 365 days. Replacing the eight idle hours with 3 W sleep reduces the annual estimate by $41.61. The same calculation works with your own currency and tariff.
Avoid counting losses twice
Use a suitable meter according to its instructions. A wall-power reading already includes the power supply's losses. A power supply's rated output is not a measurement of the computer's current consumption. Include the monitor and accessories only if the measured value covers them; otherwise calculate their usage separately.
Sleep can interrupt ongoing work, downloads or services. Compare a schedule that fits what the computer actually needs to do. A negative saving means the entered sleep power is higher than idle power; check those measurements.
This estimate excludes fixed electricity charges, tier changes and future tariff changes. For a single constant load, use the electricity calculator. For connectivity planning, try file transfer time.