Homelab electricity cost by watts
Anything that runs all day costs its wattage times 24 hours times 365 days, divided by 1,000, times your price per kWh. This table does that math for common loads.
Cost to run 24 hours a day
| Watts | kWh per year | Per year at $0.10/kWh | Per year at $0.15/kWh | Per year at $0.20/kWh | Per year at $0.30/kWh | Per month at $0.15 |
|---|---|---|---|---|---|---|
| 10 | 87.6 | $8.76 | $13.14 | $17.52 | $26.28 | $1.09 |
| 25 | 219 | $21.90 | $32.85 | $43.80 | $65.70 | $2.74 |
| 50 | 438 | $43.80 | $65.70 | $87.60 | $131.40 | $5.48 |
| 100 | 876 | $87.60 | $131.40 | $175.20 | $262.80 | $10.95 |
| 150 | 1,314 | $131.40 | $197.10 | $262.80 | $394.20 | $16.43 |
| 250 | 2,190 | $219.00 | $328.50 | $438.00 | $657.00 | $27.38 |
| 400 | 3,504 | $350.40 | $525.60 | $700.80 | $1051.20 | $43.80 |
| 600 | 5,256 | $525.60 | $788.40 | $1051.20 | $1576.80 | $65.70 |
| 1000 | 8,760 | $876.00 | $1314.00 | $1752.00 | $2628.00 | $109.50 |
Worked example
A 100 W server at $0.15 per kWh: 100 x 24 x 365 / 1000 = 876 kWh a year, and 876 x 0.15 = $131.40 a year, or $10.95 a month.
Questions
How do I find my price per kWh?
It is on your electric bill, usually with taxes and fees broken out. Use the all-in price (total bill divided by kWh used) for the most realistic number.
Does a 100 W label mean it uses 100 W?
Not always. The label is often a maximum or a power-supply rating. A plug-in power meter shows what the device actually draws.
Does cooling cost extra?
Yes, if you cool the room. The calculator can add a cooling overhead; this table shows the device load only.
Use it on your own numbers
Numbers on this page are calculated by formula when the site is built and are planning aids, not tax or engineering advice. How we check.