Guesswork is the enemy of honest energy planning. A plug-in power meter costs very little and removes all the guessing, because it tells you precisely what your rig pulls from the wall under real conditions. Here is how to read one and turn the number into a monthly cost you can trust.

Measure under real load

Plug the meter into the wall and your rig into the meter. Then mine normally for at least an hour. Idle and start-up readings are misleading; you want the steady-state figure with both CPU and GPU working as they will day to day. Note the watts displayed once it settles.

Account for the whole system

The meter measures everything behind it: the power supply inefficiency, the motherboard, drives, fans, and any monitor left on. That is exactly what you want, because that is what you actually pay for. If your monitor sleeps when you are away, take a reading with it off too.

Convert watts to kilowatt-hours

Electricity is billed in kilowatt-hours. The arithmetic is simple: watts divided by one thousand gives kilowatts, and kilowatts multiplied by hours gives kilowatt-hours. A rig drawing 220 watts running continuously uses roughly 0.22 kilowatts times 24 hours, about 5.3 kilowatt-hours per day.

Apply your tariff

  • Find the per-kilowatt-hour rate on your electricity bill.
  • Multiply your daily kilowatt-hours by that rate for a daily cost.
  • Multiply by thirty for a monthly estimate.

Continuing the example, 5.3 kilowatt-hours a day at a typical residential rate gives a modest daily figure that, over a month, is a number you can plan around rather than fear.

Watch for time-of-use rates

If your tariff changes by time of day, your average rate is not the headline number. Measure how many of your mining hours fall in cheaper periods and weight accordingly. Shifting heavy mining to off-peak hours can meaningfully lower the bill.

Why measuring beats estimating

Manufacturer wattage ratings describe maximums, not your real draw. A measured figure reflects your exact hardware, settings, and power cap. It will not promise that mining pays for itself, but it tells you the true cost so you can decide for yourself with clear eyes.