Computer Electricity Cost Calculator
Calculate a desktop or gaming PC's daily and monthly electricity cost from separate idle and load power draw and hours in each state.
Idle
W
hrs
Load / Active Use
W
hrs
$
/ kWh
Results
Daily Cost
$0.56
Daily Energy Use
3.76 kWh
Monthly Cost
$16.92
Annual Cost
$205.86
How to Calculate Your PC's Electricity Cost
A desktop or gaming PC's power draw swings a lot more than most household appliances — it might idle at 50-80W while sitting at a desktop, then jump to 300W or more under gaming or heavy load. Because of that swing, this calculator uses two separate wattage figures — idle and load — each with its own daily hours, rather than the single fixed wattage most generic electricity cost calculators assume.
Daily Cost = Daily kWh × Price per kWh
Example
A gaming PC idling at 60W for 16 hours a day and gaming at 350W for 8 hours a day uses (60 × 16 + 350 × 8) ÷ 1000 = 3.76 kWh per day. At $0.15 per kWh, that's $0.56 a day, about $16.92 a month, and roughly $205.86 a year.
Common Use Cases
- Estimating the true running cost of a gaming PC or workstation.
- Comparing electricity costs between a more efficient and a power-hungry build.
- Understanding how much heavy gaming or rendering sessions add to a power bill.
FAQs
How do I find my PC's idle and load wattage?
A plug-in power meter (like a Kill A Watt) gives the most accurate real-world reading. Without one, software tools like HWMonitor or your GPU's companion app can estimate component power draw, or you can add up your PSU-rated wattages for components and estimate 20-30% for idle draw versus full rated load for gaming.
How is this different from a generic kWh cost calculator?
A generic appliance calculator assumes one fixed wattage for the whole time it's used, which works fine for something like a space heater. A computer spends most of its time idling at low power and only occasionally draws its peak wattage, so splitting the calculation into idle and load states gives a much more realistic cost estimate.
Does this include monitors and peripherals?
No — this estimates the PC tower itself. Add a monitor's wattage (commonly 20-40W) separately if you want to include it, since monitors typically run whenever the PC is actively in use.