Electricity Cost Calculator for PCs, Servers, and NAS
Calculate electricity consumption and costs: enter wattage, quantity and hours per day, then see the costs per year, month and day with a step-by-step calculation. Free, no sign-up, directly in your browser. At the example price of €0.35 per kWh, a 30 W home server running continuously costs €91.98 per year.
Built by Luca Stanek
- Step-by-step calculation
- Up to 12 devices
- VPS comparison
- No sign-in required
Does your server at home cost you electricity every month? A VPS runs in a data center, with electricity and hardware included.
Devices
Add device
Estimates. For greater accuracy, use a plug-in power meter.
Rate and operation
Example value—enter your electricity rate.
Result
Annual electricity costs
€91.98
- Per month
- €7.67
- Per day
- €0.25
- Annual consumption
- 262.8 kWh
- Total power
- 30 W
262.8 kWh per year at €0.35 per kWh costs €91.98 per year, or €7.67 per month.
Calculation steps (4)
- 1Home server / NAS: 30 W × 1 × 24 h ÷ 1000 = 0.72 kWh per day
- 2Per year: 0.72 kWh × 365 days = 262.8 kWh
- 3Cost per year: 262.8 kWh × €0.35 = €91.98
- 4Cost per month: €91.98 ÷ 12 = €7.67
Electricity alone costs €7.67 per month here. A ZAP-Hosting VPS starts at €7.29 / month, with electricity and hardware included.
View VPSWhy this calculator
IT device electricity consumption and costs at a glance
For home servers, NAS, PCs and networking—in everyday use and in the AP1 exam.
Built for IT devices
Eight presets, from Raspberry Pi to rack server, plus custom devices with their own wattage.
Multiple devices in one calculation
Up to 12 devices, each with a quantity and daily runtime, combined into one result.
Step-by-step calculations, just like in the exam
From watts to kWh to costs, step by step and ready to copy.
Continuous operation or working days
365, 250 or 220 operating days per year, or a custom value.
Free in your browser
No sign-up required. Your values appear only in the address bar so you can share the calculation.
Comparison with a VPS
Your device's electricity costs alongside the VPS price.
How it works
Calculate your electricity costs in six steps
No account needed, right in your browser.
Step 1
Choose a device
Choose a preset such as home server / NAS, gaming PC or router, or add a custom device.
Step 2
Enter wattage, quantity and run time
Enter the wattage, quantity and hours per day, or use the preset estimates.
Step 3
Add more devices
Add up to 12 devices if needed; their power ratings and consumption are added together.
Step 4
Enter electricity price
Replace the example value with your per-kWh energy rate from your electricity bill.
Step 5
Choose operating days
Choose 365 days for continuous operation, 250 or 220 for working days, or enter your own value.
Step 6
View and share the result
See costs per year, month and day, consumption in kWh and calculation steps, then copy the result or share a link.
Formulas
How to calculate electricity costs
The formulas from the first part of the IT specialist exam, each with an example.
Energy from power and time
kWh = watts × hours ÷ 1000
Home server: 30 W × 24 h ÷ 1000 = 0.72 kWh per day
Annual consumption
kWh per year = kWh per day × operating days
0.72 kWh × 365 days = 262.8 kWh
Costs
Cost = kWh × price per kWh
262.8 kWh × €0.35 = €91.98 per year
Rule of thumb for continuous operation
1 W around the clock = 8,76 kWh per year
At €0.35 per kWh, each watt of continuous power costs around €3.07 per year
Multiple devices
Sum of watts × quantity × hours
10 office PCs, 60 W, 8 h, 250 days = 1,200 kWh, €420.00 per year
Power from voltage and current
P = U × I
230 V × 0,5 A = 115 W
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FAQ
Frequently asked questions
Quick answers about electricity consumption and costs.
Watts × hours per day ÷ 1000 gives you kWh per day. Multiply by operating days for annual consumption, then by the price per kWh for annual costs. Divide by 12 for monthly costs. Calculate each device separately and add the results.
kWh = watts × hours ÷ 1000. A 30 W home server uses 0.72 kWh in 24 hours; 1,000 W for one hour is exactly 1 kWh. Watts measure a device's power, while kWh measure the energy you pay for. The calculator shows daily consumption in the calculation steps and annual consumption in the result.
Use the per-kWh energy rate from your electricity bill, including taxes. Don't include the fixed charge: you pay it even if you use no electricity. The cost of 1 kWh depends on your tariff; the prefilled value of €0.35 is just an example, not a current market price.
The calculator presets are estimates: an office PC at 60 W for 8 hours a day, a gaming PC at 350 W for 4 hours, and a monitor at 25 W for 8 hours. A home server / NAS at 30 W, Raspberry Pi at 5 W, used rack server at 150 W, router at 10 W and switch at 20 W are each set to run around the clock. A plug-in power meter gives you a more accurate measurement.
At the example rate of €0.35 per kWh, a 350 W gaming PC running 4 hours a day costs about €178.85 a year; a 150 W rack server running continuously costs around €459.90.
Yes. You can enter up to 12 devices, each with its own wattage, a quantity of up to 1,000 and a runtime of 0 to 24 hours per day. For operating days, choose 365 for continuous operation, 250 or 220 for working days, or enter your own value from 1 to 366.
Start with the formula, then work through the steps: watts × hours ÷ 1000 gives you kWh per day; multiply by operating days for kWh per year, then by the price per kWh for the cost. Check whether the problem specifies 365 days or working days, for example in the AP1 exam for IT specialists, and round only at the end. You can copy the calculator's steps and compare them with your answer.
No. The calculator is free, requires no sign-up and runs directly in your browser. Your values appear only in the address bar so you can share the calculation via a link.
Any more questions?
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