Homelab Power Cost Calculator
What does it actually cost to run a server, NAS, or mini PC 24/7?
The sticker price on a used rack server or a new mini PC is only part of the decision. A device that idles at 150W instead of 15W will quietly cost you an extra $200 or more a year in electricity if it's on around the clock, often more than the hardware itself saved you up front. Plug in your own numbers below, or start from a preset for common homelab gear.
Your Setup
Leave this at 24 for something that's always on. Lower it if you only run the device part of the day.
Not sure of your rate? Check the cents-per-kWh line on a recent electric bill. The U.S. residential average was about 18.6¢/kWh in EIA's March 2026 data (Kansas: about 15.3¢), but it varies a lot by state and utility.
Estimated Cost
0 kWh/month at 65W, 24h/day. Estimate only: real draw varies with load, and this doesn't include the cost of cooling the space the device is in.
How Much Does It Cost to Run a Home Server? Worked Examples
The formula: watts × hours per day × 365 ÷ 1,000 = kWh per year, then kWh × your rate = dollars per year. Something that draws 100W around the clock uses 876 kWh a year, which is about $163 at the U.S. average of 18.6¢/kWh.
Here's what typical homelab gear costs to run 24/7, using average draw rather than the power supply's rating:
| Device (typical draw) | kWh / year | U.S. avg (18.6¢) | Kansas (15.3¢) |
|---|---|---|---|
| N100 mini PC or used 1L business mini (13W) | 114 | $21/yr | $17/yr |
| 4-bay NAS with spinning drives (50W) | 438 | $81/yr | $67/yr |
| Used 1U server, e.g. R630 (150W) | 1,314 | $244/yr | $202/yr |
| Used 2U server full of drives, e.g. R730xd (200W) | 1,752 | $325/yr | $269/yr |
The gap is the point: swapping a 150W 1U server for a 13W mini PC saves about $223 a year at the U.S. average, which is more than most used mini PCs cost. If the workload is DNS, a reverse proxy and a few containers, that usually decides it. If you need 256GB of ECC RAM or twelve drive bays, the server's power bill is the price of those.
These wattages are typical idle-heavy averages, not specs; the mini PC figure matches measured idle draw for N100 boxes and 1L business minis (see the idle power table). Measure your own if you can (see below). Current used prices for the hardware in the table are on the SFF / mini PC, NAS and server trackers.
Idle vs. Load: Why Your Actual Draw Matters
A server's power supply is rated for its worst case, not what it actually pulls sitting around waiting for work. Most homelab gear spends the majority of its time near idle, with short bursts under load. For a realistic number, run this calculator twice: once for your idle wattage across most of the day, once for load wattage across the busy hours, then add the two monthly totals together.
How to Measure What You're Actually Using
Don't guess if you don't have to. A cheap inline meter like a Kill-A-Watt gives you an exact reading for anything plugged into a wall outlet. A smart plug with energy monitoring (Kasa, Shelly, TP-Link) does the same thing and logs it over time. Enterprise gear with a BMC (iDRAC, iLO, IPMI) usually reports live power draw in its web UI or via ipmitool, no extra hardware needed.
Don't Forget Cooling
Every watt a server draws eventually leaves as heat, and if that heat is in an air-conditioned room, your AC has to work harder to remove it. That's a hidden cost this calculator doesn't include. Datacenters track this as PUE (Power Usage Effectiveness). For a single mini PC in a normal house it's usually negligible; for a rack of 2U servers running warm, that summer AC bill can climb noticeably.
Frequently Asked Questions
Quick answers on figuring out what your homelab gear costs to run.
Does this calculator account for idle vs. full-load power draw?
Not automatically. It assumes a single constant wattage for however many hours per day you set. Real servers and NAS units draw less power idle than under load, so for the most realistic number, run the calculator twice: once with your typical idle draw for the hours it's mostly sitting there, and once with load draw for the hours it's busy, then add the two monthly figures together.
What's a realistic average wattage for a mini PC, NAS, or rack server?
Very roughly: a newer mini PC (Intel NUC, N100 boxes) idles around 10-20W. A 4-bay NAS with spinning drives runs 40-60W. A 1-liter business mini PC (OptiPlex Micro, EliteDesk Mini, ThinkCentre Tiny) typically idles around 12-16W, about the same as an N100 box. A 1U rack server idles around 100-150W and can pull 250W+ under load. A 2U server or one packed with drives can idle at 150-250W. Actual numbers vary a lot by CPU, drive count, and PSU efficiency, so treat the presets above as a starting point, not a spec.
How do I find my actual electricity rate?
Check the per-kWh rate on a recent electric bill: it's usually listed in cents per kWh under supply or generation charges. The U.S. residential average was about 18.6¢/kWh in EIA's March 2026 data, but this varies enormously by state and utility, from under 10¢ in parts of the Pacific Northwest and South to 30¢+ in California, Hawaii, and the Northeast. If your utility bills in tiers or has time-of-use pricing, use a blended average rate for a rough estimate.
Does this include the cost of cooling the room the server sits in?
No. This calculator only covers the electricity the device itself draws. If the server sits in an air-conditioned room, the heat it generates adds extra load onto your AC, which costs more electricity that this tool doesn't capture. That overhead (sometimes summarized as PUE, or Power Usage Effectiveness, in datacenters) matters more the hotter your climate and the more gear you're running. For one or two small devices in a normal house it's usually a minor factor, but a rack full of 2U servers in a warm garage is a different story.
Is an old enterprise server actually cheaper than a new mini PC once you account for power?
Often not, if it's running 24/7. A used 1U server drawing 150W costs about $245/year in electricity at the U.S. average rate, versus about $25/year for a 15W mini PC, a gap of roughly $220 every year the server is on. That can outpace the up-front savings of buying used enterprise gear within a year or two, especially for workloads (DNS, a reverse proxy, a small VM or two) that don't need server-class hardware. Enterprise servers still win on RAM capacity, PCIe lanes, ECC memory, and drive bays. Just run the numbers on power before assuming used server hardware is the cheaper option overall. See the Enterprise Server Tracker for current used pricing.
How much does it cost to run a home server 24/7?
Multiply its average draw in watts by 8.76 to get kWh per year, then multiply by your electricity rate. At the U.S. residential average of about 18.6¢/kWh (EIA, March 2026), a 13W N100 or business mini PC costs about $21 a year, a 50W 4-bay NAS about $81, a 150W used 1U server about $244 and a 200W 2U server about $325.