PC Electricity Cost Calculator
Enter your PC and monitor watts and how long you use them to see your PC power consumption and electricity cost. Use your own rate per kWh, or the Korean home rate.
Estimate from parts
Pick a CPU and graphics card to fill the PC box with a maximum-load estimate (including 75W for other parts).
Tier limits this month: 200kWh and 400kWh. Enter your home's monthly use (kWh) from your bill so the tiers are applied. Leave it blank to count 0.
KEPCO home rate (low voltage), 2026-10~2026-12. Welfare and family discounts and meter-date splits are not included.
Enter the price per kWh from your bill or your utility's rate sheet, numbers only (no currency sign).
Added to your monthly bill by the PCMonthly electricity cost
With tiered pricing, this is the bill with the PC minus the bill without it.
- Per day
- 2.4 kWh
- Per month
- 72 kWh
- Daily averageCost per day
- -
- Tier
- Tier 1 → Tier 1
PSU Calculator PC Bottleneck Check Check My PC Specs
How to work out PC power consumption and cost
Energy (kWh) = power (W) × hours ÷ 1000. Multiply that by your price per kWh to get the cost.
For example, a 300W PC used 8 hours a day uses 2.4kWh a day. Add your monitor's watts to get closer to the real figure.
Why the Korean home rate depends on the rest of your home
KEPCO's home rate raises the base charge and the price per kWh each time monthly use passes 200kWh and 400kWh. In July and August the limits widen to 300kWh and 450kWh.
So the same PC costs more in a home that already uses a lot. The calculator shows how much the PC adds on top of the rest of your home.
Real power use is lower than the PSU rating
A power supply's watts are the most it can deliver, not what the PC always draws. The parts estimate also uses the maximum figures, the same as the PSU calculator.
Power use changes with what you are doing. For an exact figure, measure it with a plug-in power meter and enter those watts.
Does sleep mode save electricity?
Sleep uses very little power, and hibernate uses even less. Use sleep for a short break and hibernate when you won't use the PC for a long time.
Common questions
How much does it cost to leave a PC on 24/7?
A 300W PC left on 24 hours a day for 30 days uses 216kWh. At your rate per kWh, multiply that number. On the Korean home rate (spring or autumn, nothing else running) it adds about ₩35,000.
What is the average monthly electricity cost of a PC?
There is no single average, as it depends on the parts and hours. A 300W PC used 8 hours a day for 30 days uses 72kWh, so try your own numbers above.
Does sleep mode lower the electricity bill?
Yes. Sleep uses very little power, and hibernate uses even less.
Does a PC use as much power as its PSU rating?
No. The rating is the most the power supply can deliver. The PC only draws what its parts use.
Why is my real bill different?
Bills can split a month across rate seasons by meter date, and add or remove items such as discounts and other fees that this calculator leaves out.
Last reviewed 2026-11-12