How do I measure the real power draw of my Monero miner?
The most reliable way to measure your Monero miner’s real power use is with a plug-in electricity meter between your computer and the wall socket. Measure the same setup with mining stopped and running, then use the difference to estimate the extra electricity mining costs you.
Measure at the wall, not just in an app
Choose a plug-in meter that shows watts (W), the rate at which your device uses electricity, and kilowatt-hours (kWh), the total electricity used over time. Make sure it supports your local voltage and the computer’s maximum power draw.
Plug your computer’s power cable into the meter, then plug the meter into the wall. Follow its safety instructions and never exceed its rating.
Software power readings can help you troubleshoot, but they often show only the processor or another component. A wall meter includes the rest of the computer and energy lost in its power supply.
Keep your measurement boundary clear:
- Measure the computer alone for a clean starting point.
- Include a monitor only if mining requires you to leave it on.
- If you use a UPS, a battery backup, measure upstream of it to include its energy losses. Avoid testing while its battery is recharging.
Compare idle and mining under the same conditions
First, stop mining and let background activity settle. “Idle” means the computer is on but doing little work.
Then take two readings:
- Baseline: Record average power with mining stopped.
- Mining: Start your usual miner and record average power after temperatures and fan speeds stabilize.
Give each test at least 10–15 minutes, and test longer if readings keep moving. Keep browser tabs, screen brightness, and other programs the same. For a browser miner, use the same browser and mining settings you normally use.
On a laptop, start with the battery charged and avoid charging during the comparison. Battery charging or discharging can distort a short test.
For example, if your computer uses 45 W without mining and 110 W while mining, the extra draw is:
110 W − 45 W = 65 W
These are example readings, not expected results for your device.
Use an energy reading for longer sessions
A momentary watt reading can miss changes caused by heat, fans, or background tasks. For a better average, reset the meter’s kWh counter and mine for several hours.
Calculate:
Average watts = kWh used ÷ hours measured × 1,000
If the meter records 0.88 kWh over eight hours, your average total draw was 110 W.
Repeat with mining stopped for a comparable period if you want a stronger baseline. Record your average hashrate, meaning how many mining calculations your miner performs each second, alongside the power reading. That helps you compare settings fairly.
Turn the reading into your actual cost
Use the extra draw if your computer would already be running anyway. Use the full draw if you keep it on specifically to mine.
Daily electricity cost = watts ÷ 1,000 × mining hours per day × price per kWh
Use the usage-based rate on your electricity bill, including applicable per-unit charges. If rates vary by time, calculate each period separately. Extra room cooling is another cost your computer’s meter will not capture.
The bottom line
Measure at the wall, average over time, and compare matching conditions. Use extra power for an already-running computer, but full power for one kept on just to mine.
