Home AI Rig Electricity Cost Calculator
Generic PC power calculators assume a gaming rig that sleeps at night. This assumes a GPU running inference around the clock, because that's what a home AI box actually does. Enter your setup to see the real daily, monthly, and yearly cost. Nothing uploaded.
Energy Use
Cost
Note
This estimate covers GPU power only - it does not include CPU, motherboard, storage, cooling fans, or PSU efficiency losses, which typically add 15-30% on top. Check your wall-measured draw with a power meter for a more accurate figure.
Home AI Server Power and Running Costs
Blending Idle and Load Power Draw
A GPU doesn't draw full power all the time. If you run inference 6 hours a day, it idles 18 hours. This calculator blends both states: if a GPU idles at 30W and loads at 350W, running it 6 hours loaded + 18 hours idle uses about 1.65 kWh/day. Over a year at $0.15/kWh, that's roughly $90 for that one GPU. Scale it by your actual usage pattern.
Beware of Hidden Costs
GPU power is only part of the story. Your CPU, motherboard, RAM, SSD, and cooling fans add another 15-30% on top. Your power supply also has losses (typically 10-15% inefficiency), meaning you draw more from the wall than your components actually use. For the most accurate figure, use a wall-mounted power meter to measure your entire rig under load.
FAQ
What is the difference between idle and load wattage?
Idle wattage is the power your GPU draws when it is powered on but not actively running inference - perhaps waiting for a request or in a lower power state. Load wattage is the power it draws while actively processing an LLM prompt. A 4090 might idle at 30-50W and hit 350-400W under load. Check your GPU's datasheet or use a power meter to measure both.
Why doesn't this include CPU and storage power?
GPU power often dominates in an AI rig, but a CPU, SSD, RAM, cooling fans, and power supply inefficiency typically add 15-30% on top. This calculator shows GPU cost separately so you can understand the main cost driver. Measure your whole rig with a wall power meter for a complete picture.
Should I assume my GPU runs at full load 24 hours a day?
No. Set the 'Hours per day at load' to match your actual usage. If you run inference 6 hours a day and the GPU idles the other 18 hours, enter 6. The calculator will blend idle and load wattage across the full 24-hour day for a realistic cost estimate.