Use this free calculator to estimate the electricity cost of running your home lab, server, or any always-on device in the UK. Enter your device wattage and electricity rate — or pick from the quick presets — and the calculator instantly shows your daily, monthly, and annual running costs.
Home Lab Power Cost Calculator
Estimate the electricity cost of running servers and home lab equipment in the UK.
Estimated costs
Daily cost
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Monthly cost
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Annual cost
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Annual energy use
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CO2 per year (UK grid)
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UK grid carbon intensity: 0.207 kg CO2/kWh. Monthly figure uses 30.44 days. Electricity rate default is the UK average for 2026 (approx. 24p/kWh). Costs are estimates only.
How to use this calculator
Enter your device’s wattage — you can usually find this on the power supply label, in the device specifications, or by measuring with a smart plug energy monitor. If you are not sure, pick from the preset buttons which give realistic averages for common home lab and server hardware.
The electricity rate defaults to 24p per kWh, which is the approximate UK average unit rate in 2026. Check your latest energy bill or your supplier’s tariff to use your actual rate. If you are on a time-of-use tariff such as Octopus Go, you may want to calculate separately for peak and off-peak hours.
How to reduce your home lab running costs
The single biggest factor in home lab energy costs is idle power draw. Older rack servers — particularly pre-2015 hardware — can draw 200–400W even when doing very little. Moving workloads to modern mini PCs or ARM-based hardware can cut running costs by 80% or more. A Raspberry Pi 5 running 24 hours a day costs around £4–5 per year at typical UK rates. A Dell PowerEdge R720 doing the same job can cost £400–500 per year.
If you are running Proxmox, consider using LXC containers rather than full VMs where possible — they use significantly less RAM and CPU overhead, reducing load and therefore power draw. See our Proxmox hardware guide for UK buying recommendations.
