How to measure your PC’s real power use
Use a plug-in energy meter to measure what your PC draws while gaming, idle and asleep, and why software readings differ.
The most accurate way to know what your PC costs to run is to measure it at the wall. A plug-in energy meter costs about the same as a game and shows exactly what your electricity meter sees.
What you need
- A plug-in energy meter rated for your country’s sockets (sold as “energy monitor”, “Strommessgerät”, “wattmetro”, “vatímetro” or “wattmètre”).
- Ideally a power strip, so the PC and monitor can be measured together or separately.
How to measure
- Plug the meter into the wall and the PC into the meter. Measure the monitor separately if you want to know its share.
- Gaming: play a demanding game for at least 10 minutes, then read the average or note the typical value. Readings jump around; ignore one-second peaks.
- Idle: leave the desktop open with nothing running for 5 minutes and read the value.
- Sleep and off: put the PC to sleep and read the value, then shut it down and read it again.
- If the meter has an energy counter, reset it and let it run for a full day of normal use. kWh per day × your price × 30 is your monthly cost.
Why software readings are different
Tools like HWiNFO or the GPU driver overlay report what individual components say they draw, before power supply losses. Your wall reading is higher because it includes the power supply’s conversion loss, the motherboard, memory, drives, fans and lighting. That is why our calculator divides component power by the power supply efficiency.
Share your measurement
Our gaming figures for most parts are estimates. Real wall measurements make them better for everyone. Send us your reading.