Home Server Electricity Cost Calculator

The Formula

Calculating your home server’s electricity cost takes one formula:

Annual cost = (Watts × 24 × 365) / 1000 × $/kWh

Simplified: Watts × 8.76 × $/kWh = annual cost

The 8.76 comes from 8,760 hours in a year divided by 1,000 to convert watts to kilowatts. Memorize this multiplier or bookmark this page.

Quick Multipliers by Electricity Rate

Electricity Rate	Region	Multiplier (Watts × this = annual $)
$0.08/kWh	Louisiana, India, parts of Canada	Watts × $0.70
$0.10/kWh	Canada average	Watts × $0.88
$0.12/kWh	US average	Watts × $1.05
$0.20/kWh	Global average, Australia	Watts × $1.75
$0.25/kWh	California, parts of US	Watts × $2.19
$0.28/kWh	UK average	Watts × $2.45
$0.30/kWh	EU average	Watts × $2.63
$0.35/kWh	Germany	Watts × $3.07

How to use this table: Find your electricity rate, then multiply your server’s idle wattage by the multiplier. A 10W idle mini PC at US rates: 10 × $1.05 = $10.50/year. That same mini PC at German rates: 10 × $3.07 = $30.70/year.

Check your electricity bill for your actual per-kWh rate. The number on the bill is what matters, not the regional average.

Monthly Cost

Divide the annual figure by 12. Or use the monthly multiplier: Watts × 0.73 × $/kWh = monthly cost.

A 6W N100 mini PC at $0.12/kWh: 6 × 0.73 × 0.12 = $0.53/month. Less than a cup of gas station coffee.

Power Consumption by Hardware Type

These are real-world measurements taken at the wall with a Kill A Watt meter, not manufacturer TDP ratings. TDP tells you maximum heat output, not how much the system actually draws from the outlet.

Mini PCs

The sweet spot for self-hosting. Low power, quiet, capable.

Device	CPU	Idle	Light Load	Full Load	Annual Cost (Idle, $0.12/kWh)
Beelink S12 Pro	Intel N100	6W	8-10W	15W	$6.30
Beelink EQ12	Intel N100 (dual 2.5GbE)	7W	9-12W	18W	$7.35
GMKtec NucBox G3	Intel N100	6W	8-10W	15W	$6.30
Beelink EQ12 Pro	Intel N305	10W	13-17W	35W	$10.50
Beelink SER5 Pro	AMD Ryzen 5 5560U	12W	16-20W	38W	$12.60
Minisforum UM790 Pro	AMD Ryzen 9 7940HS	15W	22-28W	68W	$15.75
Intel NUC 12 Pro	Intel i5-1240P	12W	25-35W	65W	$12.60
Intel NUC 13 Pro	Intel i7-1360P	14W	28-38W	70W	$14.70

“Light load” means running 5-15 Docker containers with moderate use (Nextcloud, Jellyfin, Pi-hole, Home Assistant, etc.). This is where most home servers sit 95% of the time.

Single Board Computers

Lowest power draw, but limited CPU and RAM constrain what you can run.

Device	Idle	Full Load	Annual Cost (Idle, $0.12/kWh)
Raspberry Pi 4 (4GB)	3W	7W	$3.15
Raspberry Pi 5 (8GB)	4W	12W	$4.20
Orange Pi 5 (8GB)	4W	15W	$4.20
ODROID-N2+	4W	10W	$4.20

A Raspberry Pi 5 costs $4.20/year to run 24/7. That is not a typo. The trade-off is ARM compatibility issues, limited RAM (8GB max), and USB-attached storage bottlenecks.

NAS Devices (Pre-built)

NAS power draw scales primarily with the number of spinning hard drives. The NAS unit itself draws 8-12W; each 3.5” HDD adds 4-6W.

Device	Idle (no drives)	Idle (2 drives)	Idle (4 drives)	Active (4 drives)	Annual Cost (Idle w/ drives, $0.12/kWh)
Synology DS224+	8W	16W	-	-	$16.80 (2-bay)
Synology DS423+	9W	-	24W	32W	$25.20 (4-bay)
Synology DS923+	10W	-	25W	35W	$26.25 (4-bay)
QNAP TS-464	12W	-	28W	40W	$29.40 (4-bay)
Synology DS1621+	15W	-	38W*	55W*	$39.90 (6-bay)*

*Estimated based on 6 drives.

The DS224+ with two 8TB drives idles at around 16W, costing $16.80/year. That is dramatically cheaper than any cloud storage subscription for 16TB of raw capacity.

Used Business PCs

Excellent value if you buy used. Power draw depends heavily on generation and form factor.

Device	CPU	Form Factor	Idle	Load	Annual Cost (Idle, $0.12/kWh)
Dell OptiPlex 5060 Micro	i5-8500T	Micro (1L)	15W	50W	$15.75
Dell OptiPlex 7050 Micro	i7-7700T	Micro (1L)	20W	55W	$21.00
Dell OptiPlex 5060 SFF	i5-8500	Small Form Factor	22W	65W	$23.10
Dell OptiPlex 7060 SFF	i7-8700	Small Form Factor	25W	80W	$26.25
Lenovo ThinkCentre M920q	i5-8500T	Tiny (1L)	12W	38W	$12.60
Lenovo ThinkCentre M720q	i5-8400T	Tiny (1L)	10W	35W	$10.50
HP EliteDesk 800 G4 Mini	i5-8500T	Mini (1L)	14W	45W	$14.70

Micro/Tiny/Mini form factors (1-liter cases) are more efficient than SFF (small form factor). They use mobile T-series or low-power desktop CPUs with better idle power states. The trade-off is fewer expansion options — usually one M.2 slot and no room for 3.5” drives.

Tower and Rack Servers

If you actually need ECC RAM, IPMI, and hot-swap drive bays. Most home users do not.

Device	Idle	Load	Annual Cost (Idle, $0.12/kWh)
Dell PowerEdge T340	50W	200W	$52.50
Dell PowerEdge T440	80W	350W	$84.00
HP ProLiant ML350 Gen10	80W	400W	$84.00
Dell PowerEdge R730 (2U rack)	120W	500W	$126.00
HP ProLiant DL360 Gen10 (1U rack)	90W	350W	$94.50

A used rack server running 24/7 at 120W idle costs $126/year in electricity alone. At EU rates ($0.30/kWh), that jumps to $315/year. For most self-hosters, this is throwing money away. A $150 N100 mini PC handles the same workloads at 6W.

Hard Drives (Additional Per Drive)

Every drive you add increases total system power:

Drive Type	Idle	Active (Read/Write)	Spin-Up
3.5” HDD (CMR, 7200 RPM)	5-6W	8-10W	25W (brief)
3.5” HDD (SMR, 5400 RPM)	3-4W	6-8W	20W (brief)
2.5” HDD (5400 RPM)	1-2W	3W	5W (brief)
2.5” SATA SSD	0.3-0.5W	2-3W	-
M.2 NVMe SSD	0.5-2W	3-7W	-

Each 3.5” HDD adds roughly $5-6/year to your electricity bill at US rates. A 4-drive NAS adds $20-24/year just in drive power. An 8-drive NAS: $40-48/year.

SSDs are dramatically more efficient. A 2.5” SATA SSD adds $0.30-0.50/year. If your workload does not require massive HDD capacity, SSDs save real money over time.

Accessories and Add-ons

Often overlooked power draws:

Device	Power Draw
Managed switch (8-port, fanless)	5-8W
Managed switch (24-port, PoE)	15-30W (without PoE load)
Wireless access point	5-12W
USB external HDD (3.5”)	5-8W
UPS (idle, no load)	5-10W
Router (consumer)	8-15W
PoE camera (per camera)	5-12W

A typical homelab with a switch, access point, and router adds 20-35W, or $21-37/year. Factor this into your total.

Annual Cost Table (US Average: $0.12/kWh)

The complete picture for common self-hosting configurations:

Setup	Idle Watts	Monthly Cost	Annual Cost
Raspberry Pi 5	4W	$0.35	$4.20
N100 mini PC (SSD only)	6W	$0.53	$6.30
N100 mini PC + 1 HDD	11W	$0.97	$11.55
Lenovo ThinkCentre M720q	10W	$0.88	$10.50
Dell OptiPlex Micro (i5-8500T)	15W	$1.32	$15.75
2-bay NAS (2 drives)	16W	$1.41	$16.80
Dell OptiPlex SFF (i5-8500)	22W	$1.94	$23.10
4-bay NAS (4 drives)	25W	$2.19	$26.25
N100 mini PC + switch + AP	18W	$1.58	$18.90
Repurposed gaming PC	60W	$5.26	$63.00
Tower server (T340)	50W	$4.38	$52.50
Rack server (R730)	120W	$10.51	$126.00
Full homelab (server + NAS + networking)	45W	$3.94	$47.25

Annual Cost Table (EU Average: $0.30/kWh)

Same setups, 2.5x the cost. This is where efficient hardware pays for itself fast.

Setup	Idle Watts	Monthly Cost	Annual Cost
Raspberry Pi 5	4W	$0.88	$10.50
N100 mini PC (SSD only)	6W	$1.31	$15.75
N100 mini PC + 1 HDD	11W	$2.41	$28.88
Lenovo ThinkCentre M720q	10W	$2.19	$26.25
Dell OptiPlex Micro (i5-8500T)	15W	$3.29	$39.38
2-bay NAS (2 drives)	16W	$3.50	$42.00
Dell OptiPlex SFF (i5-8500)	22W	$4.82	$57.75
4-bay NAS (4 drives)	25W	$5.48	$65.63
Repurposed gaming PC	60W	$13.14	$157.50
Tower server (T340)	50W	$10.95	$131.25
Rack server (R730)	120W	$26.28	$315.00
Full homelab (server + NAS + networking)	45W	$9.86	$118.13

At EU rates, a rack server costs $315/year just to keep turned on. An N100 mini PC running the same services costs $15.75. That $299/year difference buys a new mini PC every year with money to spare.

How to Measure Your Server’s Power Consumption

Do not trust manufacturer specs. TDP is a thermal rating, not a power meter reading. Published “typical power” figures are often measured under unrealistic conditions. The only way to know your actual consumption is to measure it.

Plug-in Power Meters

The most accurate approach. Plug the meter between the wall outlet and your server, read the display.

Kill A Watt P3 P4400 (~$25) — The standard recommendation. Large display, measures watts, amps, volts, kWh over time. Plug in your server, check the wattage reading after 10 minutes of idle to get a stable number. Leave it for 24 hours to get a kWh reading, then multiply by 365 for annual consumption.

Kill A Watt EZ P4460 (~$30) — Same as above but can calculate cost directly. Enter your electricity rate and it shows dollars.

Smart Plugs with Power Monitoring

More convenient for ongoing tracking. They report power consumption to an app on your phone.

TP-Link Tapo P110 (~$15) — Budget pick. Reports wattage, tracks daily/monthly consumption in the Tapo app. Also gives you remote power control, which is handy for remote reboots. 15A rated, more than enough for any home server.

TP-Link Kasa EP25 (~$18) — Same power monitoring, works with the Kasa ecosystem instead. Matter-compatible.

Shelly Plug S (~$20) — Works with Home Assistant natively. If you are already running Home Assistant, this feeds power data directly into your dashboards and automations.

Smart plugs have 1-3% measurement error compared to dedicated meters. Good enough for cost estimation.

UPS with Monitoring

If you already have a UPS (and you should for any server with spinning drives), many models report load wattage:

CyberPower CP1500PFCLCD — reports watts on the LCD and via USB/NUT
APC Back-UPS Pro BR1500MS2 — reports via USB/PowerChute or NUT

Connect via USB and use NUT (Network UPS Tools) to log power draw over time. No additional hardware required.

What to Measure

Idle power — the number that matters most. This is what your server draws 95%+ of the time.
Typical load — start your usual containers, let the system settle for 10 minutes, then read.
Peak load — run a CPU stress test (stress-ng --cpu $(nproc) --timeout 60). This tells you worst-case draw and helps size your UPS.

Idle power is what determines your annual cost. Peak power barely matters unless you are transcoding video 24/7.

Tips to Reduce Power Consumption

1. Use Mini PCs Instead of Tower Servers

This is the single biggest change you can make. A 6W N100 mini PC runs Nextcloud, Jellyfin, Pi-hole, Home Assistant, Vaultwarden, and a dozen other containers without breaking a sweat. A tower server doing the same work idles at 50-80W. The annual cost difference: $46-78/year.

Unless you need more than 64GB of RAM, ECC memory, or more than 2 NVMe slots, a mini PC is the right answer.

2. Replace HDDs with SSDs Where Possible

Each 3.5” HDD adds 5-6W idle. Four drives add 20-24W, costing $21-25/year just in drive power. If you do not need multi-terabyte bulk storage, a 2TB NVMe SSD ($100-120) draws 1W and stores plenty for most self-hosting workloads.

Keep HDDs for media libraries and cold storage. Use SSDs for everything else.

3. Enable CPU Power Management in BIOS

Most BIOSes have power management settings that are sometimes not set to the most efficient defaults:

C-states — deeper idle states. Enable all available C-states (C6, C7, C8, C10). Each deeper state reduces idle power.
SpeedStep / Speed Shift (Intel) or Cool’n’Quiet (AMD) — allows the CPU to drop frequency when idle. Should be enabled.
Package C-state limit — set to the deepest available (C10 if offered).
Power profile — if your BIOS has a power profile setting, choose “Low Power” or “OS Controlled.”

On an Intel N100, properly configured C-states can drop idle power from 8W to 6W. On larger CPUs, the savings are bigger.

4. Spin Down Idle Hard Drives

If you have HDDs that are not accessed continuously, configure them to spin down after a timeout:

# Spin down after 20 minutes of inactivity (value 240 = 20 min)
sudo hdparm -S 240 /dev/sda

Or configure in your NAS software — Synology DSM, TrueNAS, and Unraid all have drive standby settings.

A spun-down 3.5” HDD draws roughly 1W instead of 5W. Four idle drives save 16W, or $16.80/year.

Caveat: Frequent spin-up/spin-down cycles increase wear on HDDs. If drives are accessed multiple times per hour, leave them spinning. Spin-down is best for drives accessed a few times per day (backup drives, media archives).

5. Consolidate Services onto Fewer Machines

One 10W server running 20 Docker containers uses less power than two 10W servers running 10 containers each. Every additional machine adds its own idle overhead (PSU, RAM, NIC, SSD).

Before adding a second server, ask: does the first one actually need help? An N100 can run 30+ lightweight containers. A Ryzen 5 mini PC handles 50+.

6. Disable Unused Hardware

Wi-Fi — disable in BIOS if the server uses Ethernet. Saves 0.5-1W.
Bluetooth — disable in BIOS. Saves 0.2-0.5W.
Audio — disable onboard audio in BIOS. Saves 0.2W.
Extra Ethernet ports — if your mini PC has dual NICs and you only use one, the second still draws power when linked but idle.
USB devices — unplug anything you do not need.

These are small individual savings, but they add up. Disabling Wi-Fi, Bluetooth, and audio on an N100 can shave 1W off idle, saving about $1/year.

7. Use Wake-on-LAN for Infrequent Tasks

If you have a more powerful server that only runs occasional workloads (Plex transcoding, backups, batch processing), do not leave it on 24/7. Use Wake-on-LAN to start it remotely when needed.

Your always-on low-power server (N100 or Pi) sends a WoL magic packet to the big server. The big server boots, does its work, then shuts down or suspends.

A 60W gaming PC used 4 hours/day instead of 24/7 drops from $63/year to $10.50/year.

8. Avoid Repurposed Gaming PCs

A gaming PC idling at 60-100W costs $63-105/year. It was designed for burst performance with a beefy PSU, discrete GPU, and multiple fans — none of which help a server workload that idles 95% of the time.

Sell the gaming PC and buy a $150 N100 mini PC. You will save the purchase price in electricity within 2 years.

Is Self-Hosting Cheaper Than Cloud Services?

The electricity cost of self-hosting is almost always trivial compared to cloud subscription fees. The real cost comparison includes hardware amortization.

Quick Break-Even Analysis

Cloud Service	Annual Cost	Self-Hosted Equivalent	Hardware Cost	Annual Electricity	Break-Even
Google One 2TB	$100/year	NAS + 2×4TB drives	$350	$17/year	4.2 years
iCloud+ 2TB	$120/year	NAS + 2×4TB drives	$350	$17/year	3.4 years
Dropbox Plus 2TB	$120/year	Nextcloud on N100	$200	$7/year	1.8 years
Google Workspace	$84/year	Nextcloud + Collabora	$200	$7/year	2.6 years
1Password Family	$60/year	Vaultwarden on N100	$150	$7/year	2.8 years
Plex Pass (lifetime)	$120 one-time	Jellyfin on N100	$150	$7/year	N/A (Jellyfin is free)

After break-even, you save the full subscription cost every year — minus the small electricity cost. A $200 mini PC replacing $200/year in cloud subscriptions pays for itself in year one and saves $193/year after that.

For a deep dive with 5-year TCO projections, see our full analysis: Self-Hosting vs Cloud: Cost Comparison.

FAQ

How much does it cost to run a home server 24/7?

It depends entirely on your hardware. A Raspberry Pi 5 costs $4.20/year. An Intel N100 mini PC costs $6.30/year. A 4-bay NAS with drives costs $26.25/year. A used rack server costs $126/year. All figures at $0.12/kWh. For most self-hosters running a mini PC or small NAS, expect $7-30/year.

Is a Raspberry Pi cheaper to run than a mini PC?

By about $2-3/year. A Pi 5 idles at 4W ($4.20/year) versus 6W ($6.30/year) for an N100 mini PC. That $2.10/year savings is unlikely to justify the Pi’s limitations: 8GB max RAM, USB storage only, ARM compatibility issues, and less CPU performance. The N100 is the better value for most self-hosting use cases.

How do I reduce my home server’s power bill?

The biggest lever is hardware choice. Switch from a tower server to a mini PC and save $50-100/year. After that: replace HDDs with SSDs where possible, enable CPU C-states in BIOS, disable unused peripherals (Wi-Fi, Bluetooth, audio), and consolidate services onto fewer machines. See the full tips section above.

Does running Docker containers increase power consumption?

Barely. Docker containers share the host OS kernel and do not run separate operating systems. An idle container uses essentially zero additional power. A container under load uses CPU and RAM, which increases power proportionally — but no more than the same process would use running natively. Going from 5 containers to 25 containers on an N100 might add 1-2W at idle.

Should I worry about electricity costs when choosing self-hosting hardware?

Only if you are choosing between dramatically different hardware tiers. The difference between an N100 (6W) and an N305 (10W) is $4.20/year — irrelevant. The difference between an N100 (6W) and a rack server (120W) is $119.70/year — significant. Choose hardware based on your actual compute needs first, then optimize power within that tier.

How much does a homelab cost in electricity per month?

A typical homelab with a mini PC server (6-15W), a managed switch (6W), and an access point (8W) runs 20-30W total, costing $1.75-2.63/month at US rates. Add a 4-bay NAS with drives and you are at 45-55W, or $3.94-4.82/month. Under $60/year for a complete setup.