AI and automation
Self-Hosted Server Electricity Cost Calculator
Estimate what it costs to run a home server, NAS, mini PC, or local AI workstation all month.
When to use this
Use it before a self-hosted box runs 24/7
This calculator is for homelabs, Open WebUI boxes, NAS devices, media servers, mini PCs, GPU rigs, and automation servers where the power bill is part of the hosting decision.
Default result
The server-rendered AI workstation example uses 189.6 kWh per month and costs $35.19 at the default rate.
How the server electricity cost formula works
The calculator weights active power and idle power across a 24-hour day, converts average watts into kWh, applies the overhead multiplier, then multiplies by your electricity rate.
What counts as active power?
Use active power for the workload that matters: local AI inference, transcoding, backup verification, indexing, compile jobs, game servers, or scheduled automations. If the box has several workload levels, enter a weighted average or run separate scenarios.
What to do next
Measure wall draw at idle and under load, compare the result with VPS and cloud GPU costs, and decide whether uptime, privacy, latency, and maintenance are worth the monthly power cost.
SSR example
Default math: 263 W average IT draw, 189.6 kWh per month, $35.19 monthly cost.
Worked example: AI workstation running 8 active hours per day
The default workstation uses 550 W while active for 8 hours and 120 W while idle for the remaining 16 hours.
Daily energy is 550 W x 8 h + 120 W x 16 h = 6,320 Wh, or 6.32 kWh per day. Across 30 days, that is 189.6 kWh before any overhead multiplier.
At $0.1856 per kWh and overhead multiplier 1.00, monthly cost is 189.6 x $0.1856 = $35.19. Annual cost is $35.19 x 12 = $422.28.
If the same system stayed at 550 W all day, it would use 396.0 kWh per month and cost $73.50. The mixed active/idle schedule saves about $38.31 per month versus that always-active case.
Reference data used by the defaults
| Topic | Reference value | Source | Date | Note |
|---|---|---|---|---|
| Electricity rate default | $0.1856 per kWh default, matching 18.56 cents per kWh from the U.S. residential average used in the EIA Electric Power Monthly for March 2026. | EIA Electric Power Monthly | As of June 20, 2026 | Replace with your utility bill rate, including delivery charges when you want the real marginal cost. |
| Average price table | EIA Table 5.6.A covers average retail electricity price to ultimate customers by state and end-use sector. | EIA Electric Power Monthly, Chapter 5 | March 2026 data release, published May 21, 2026 | State and tariff-specific rates can differ materially from the national residential average. |
| Overhead multiplier | The overhead input uses the PUE idea: total facility energy compared with IT equipment energy. | ISO/IEC 30134-2:2026 | Published January 2026 | For a home wall-plug estimate, use 1.00 unless you want to model cooling, UPS, or room overhead. |
Electricity rates, tariffs, taxes, and hardware power draw vary. Replace every default with your own bill and measurements before making a hosting decision.
FAQ
Should I use PSU wattage or measured wall power?
Use measured wall power when you have it. PSU capacity is not the same as real draw. If you do not own the machine yet, use vendor TDP or TGP numbers as a rough planning input and rerun the calculator after measuring idle and active draw.
Does the calculator include cooling cost?
Only if you include it in the overhead multiplier. Use 1.00 for a direct plug-load estimate. Increase the multiplier when the server adds air conditioning, UPS losses, or other facility overhead.
Why separate idle watts and active watts?
Servers often spend many hours idle, but GPUs and CPUs can jump sharply under inference, transcoding, backups, indexing, or training. Separating the two avoids sizing a full month at peak power.
What electricity rate should I enter?
Use the marginal all-in rate from your utility bill when possible: supply, delivery, riders, and taxes that scale with kWh. The EIA default is only a national planning default.
Is 24/7 self-hosting cheaper than a VPS?
Power alone can be cheaper for hardware you already own, but the full decision also includes hardware cost, backups, internet reliability, maintenance time, cooling, noise, and downtime risk.
How do I reduce the monthly cost?
Measure idle draw, enable CPU and GPU power limits, sleep disks when safe, schedule heavy jobs, shut down test boxes outside work hours, and right-size the server before adding more hardware.
Decision path
What to do next
Compare local and cloud AI
Add hardware cost, resale, maintenance, and API usage to the monthly power estimate.
Hosting tierSize a VPS alternative
Check whether a small VPS, managed database, or GPU host is cheaper than running the box at home.
HardwareSize the PSU before buying
If the workload needs GPUs, verify sustained draw, transient headroom, and cable requirements.
Topic hubOpen local AI
Connect power cost with model fit, hardware setup, self-hosting, and private AI operations.