PC Power Cost Calculator
Gaming rig, office desktop, or laptop — see exactly what it adds to your electricity bill, active and idle hours included.
Monthly electricity cost
$0
0 kWh/month
PSU ratings are maximums, not actual draw — a "750 W" PC rarely pulls over 450 W. For exact numbers, measure with a plug-in power meter.
What PCs actually draw
The cost formula is (load W × load hours + idle W × idle hours) × 30 ÷ 1,000 × rate. The trick is knowing realistic wattages — the PSU sticker is a ceiling, not a measurement:
| System | Under load | Idle | 4h load + 4h idle, monthly* |
|---|---|---|---|
| Laptop | 40–60 W | 5–15 W | ≈ $1.30 |
| Office desktop + monitor | 120–180 W | 40–60 W | ≈ $3.60 |
| Mid-range gaming PC | 300–400 W | 60–80 W | ≈ $7.60 |
| High-end gaming PC | 500–700 W | 80–100 W | ≈ $11.50 |
| Streaming/rendering rig (24/7) | 250 W avg | — | ≈ $27.00 |
*at $0.15/kWh. Two easy wins: enable sleep mode (drops to 1–5 W, unlike idle), and cap your GPU's frame rate — rendering 240 fps on a 144 Hz monitor is pure heat.
PC power FAQ
How much electricity does a gaming PC use?
300–400 W gaming for mid-range builds, 500–700 W for high-end. Four hours a day at 400 W ≈ 48 kWh/month ≈ $7 at $0.15/kWh.
How much does running a PC 24/7 cost?
At a constant 100 W: 72 kWh/month, about $11 at $0.15/kWh ($130/yr). At 400 W: about $43/month. Sleep mode eliminates nearly all of it.
Does a laptop use much less than a desktop?
Yes — 20–60 W versus 100–400+ W. A laptop used 8 h/day costs $1–3/month, about a tenth of a gaming desktop with monitor.
How do I find my PC's actual wattage?
Use a plug-in power meter, read component power in HWiNFO, or estimate CPU TDP + GPU TDP + ~50 W. The PSU rating is only a maximum.