Homelab power cost calculator
Add your devices, set your electricity price, and see what the lab costs to run per month and per year. Presets are typical values; use a plug-in power meter or the BMC reading for your own numbers.
| Device | Watts | Hours/day |
|---|
Presets:
Ways to cut the bill
- Idle draw matters most: a server idling at 120 W around the clock uses over 1,000 kWh a year.
- Consolidate small boxes onto one efficient host, and spin down drives that are rarely used.
- Power-limit GPUs (nvidia-smi -pl): inference usually loses little speed.
- Old servers often idle at 2-3x the power of a modern mini PC doing the same job.
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Related: PDU calculator, power connector guide.
Frequently asked questions
How do I calculate the running cost of a server?
Watts × hours ÷ 1000 gives kWh. Multiply kWh by your price per kWh. A 100 W device running all month uses about 73 kWh.
Should I use idle or peak watts?
Use the average draw you measure with a power meter or the PDU. Peak watts overstate the bill.
What is the overhead percentage for?
It covers cooling, UPS losses and network gear that runs because of the servers.