Beyond picking the right PSU, it’s often useful to know roughly what your PC actually costs to run — whether you’re budgeting monthly electricity costs, comparing two possible builds, or just curious how much that GPU upgrade adds to your bill. This calculator estimates your system’s power draw at idle and under gaming load, and converts that into an approximate running cost using your local electricity rate. It’s aimed at anyone planning a build, comparing components, or trying to understand where their PC’s power actually goes.
| Build | From the wall, gaming | From the wall, idle | Per month |
|---|---|---|---|
| Ryzen 5 5600 + RTX 4060 | 278W | 64W | $4.62 |
| Ryzen 5 7600 + RTX 4070 Super | 397W | 84W | $6.49 |
| Ryzen 7 7800X3D + RTX 4080 | 539W | 113W | $8.79 |
| Core i9-14900K + RTX 4090 | 762W | 138W | $12.15 |
Per month = 3 hours of gaming and 3 hours of idle or light use a day for 30 days, at $0.15 per kWh, with 2 RAM sticks, 2 drives and 3 fans.
How this is calculated: the formula on our Methodology page. Sources: part specs from each maker’s official product page (our hardware database).
Quick answer
This calculator estimates your whole system’s power draw at idle and under gaming load — combining baseline draw from the motherboard, RAM, storage, and fans with the CPU’s typical gaming draw and the GPU’s rated board power, then adding the power supply’s own efficiency loss — then converts that into an electricity cost estimate using your entered usage hours and rate. The GPU is typically the single biggest consumer once the system is under load.
How Many Watts Does a Gaming PC Use?
In the example builds above, a gaming PC draws about 278W from the wall while gaming with a Ryzen 5 5600 + RTX 4060, and about 762W with a Core i9-14900K + RTX 4090. At the desktop the same PCs draw only 64W to 138W. The graphics card is the biggest share under load. With 3 hours of gaming and 3 hours of light use a day at $0.15 per kWh, that is about $4.62 to $12.15 a month.
What the Result Means
You’ll typically see two power figures — an idle draw (what your system uses sitting at the desktop or doing light tasks) and a load draw (what it uses under sustained gaming or heavy workloads) — plus a cost estimate based on hours of use per day or week and your electricity price per kWh. Idle draw is dominated by the baseline power the motherboard, RAM, storage, and fans need just to stay on, plus a much lower CPU and GPU draw since neither is being pushed. Load draw scales up mainly because of the CPU and especially the GPU, which is usually the single biggest power consumer in a gaming PC once it’s under load.
The cost figure is a straightforward multiplication of estimated wattage, hours of use, and your electricity rate — it’s only as accurate as those inputs, so getting your real electricity rate and a realistic estimate of your daily usage hours matters more than anything else for that number.
How This Calculator Works
The calculator estimates idle power as a smaller baseline figure built from typical low-load consumption for the motherboard, RAM, storage, and fans, plus the CPU and GPU each running near their minimum power states. Load power takes the GPU at its rated board power and the CPU at its typical gaming draw: about 55% of the manufacturer’s maximum turbo/boost power, or 45% for AMD X3D chips, which run cooler in games. That is closer to review measurements than the rated TDP, which over-states X3D chips and under-states unlocked Intel K chips. The same baseline system draw is added on top. Both figures are then divided by the power supply’s efficiency (about 88% under gaming load and 80% at idle), because the wall socket, and your bill, pays for the PSU’s losses too. The wattage figures are then converted to kilowatt-hours over your specified usage time and multiplied by your entered electricity price to produce a cost estimate, usually shown per day, month, and year.
Worked example: Take a Ryzen 5 7600 and an RTX 4070 with the default two RAM sticks, two drives and three fans. While gaming, the parts draw about 329W (the 7600 at about 48W, 55% of its 88W PPT; the RTX 4070 at 200W; 81W for the rest), which is about 374W from the wall. At idle the parts draw about 64W, or 80W from the wall. If you game for 3 hours a day and leave the PC idling for another 3 hours of light use, that is (374W × 3h) + (80W × 3h) ≈ 1.36 kWh per day. At an electricity price of $0.15 per kWh, that is about $0.20 per day, or roughly $6.13 a month: small on its own, but a useful number when comparing it against a higher-power build.
Important Limitations
This is an estimate built from typical TDP figures and baseline draw assumptions, not a measurement taken from your specific PC with a wattmeter. Actual draw depends on the specific game or workload (some games barely tax a GPU while others push it to its power limit constantly), monitor refresh rate and resolution, background applications, power-saving settings in your OS and BIOS, ambient temperature, and the specific silicon in your CPU and GPU, which can vary unit to unit. PSU efficiency is included as a typical figure (about 88% under gaming load, 80% at idle); a high-efficiency 80+ Gold or Platinum unit wastes a little less, and an older or budget unit a little more.
Electricity rates vary significantly by region, time of day (if you’re on a variable-rate plan), and season, and this calculator uses whatever flat rate you enter rather than pulling a live utility rate. Treat the cost output as a reasonable planning figure for comparing builds or estimating a monthly budget, not as a guaranteed bill amount — if you want a precise number, a plug-in power meter on your actual PC is the only way to measure real draw directly.
Frequently Asked Questions
Why does my PC use so much more power under load than at idle?
Because the CPU and especially the GPU scale their power draw enormously based on how hard they’re working. At idle, both parts sit at a low-power state; under a demanding game, the GPU in particular can draw several times its idle power, which is why load figures are so much higher than idle figures.
Does resolution affect power consumption?
Yes, indirectly. Higher resolutions typically push the GPU harder, which increases its power draw toward its rated limit, while lower resolutions on a powerful GPU may let it idle at a lower power state more often, especially if a frame rate cap is in place.
How can I actually lower my PC's power draw?
Undervolting the CPU or GPU, capping your frame rate to what your monitor needs, enabling power-saving BIOS settings, and choosing more power-efficient components at your next upgrade are the most effective levers, roughly in that order of effort versus payoff.
Is this the same as my PSU wattage?
No. Your PSU’s wattage rating is its maximum safe capacity, sized with headroom above your typical draw. This calculator estimates what your components actually consume, which should be comfortably below your PSU’s rated wattage during normal use.
Why is my estimated cost different from my actual electricity bill?
Your bill includes other devices, your utility’s exact rate structure (tiered rates, time-of-use pricing, fixed fees), and your PC’s real usage pattern, none of which this calculator can see — it only estimates the PC’s own draw at the rate and hours you enter.