Server calculator: how much RAM and CPU do I need?
Pick your self-hosting tools and the number of users – the calculator estimates RAM and CPU needs and recommends the right netcup server.
You know which services you want to self-host – but not how big the server needs to be? That’s exactly what this calculator is for: pick your tools and the number of users, and you get a concrete RAM/CPU estimate along with a matching netcup recommendation.
The values are deliberately calculated conservatively (base load for Debian + Docker plus a safety margin), so your server doesn’t run at its limit in everyday use. They are still only ballpark figures: video transcoding, large photo imports, or many simultaneous users can draw significantly more power for short bursts. When in doubt, go one size larger – or start small and grow via a server migration.
1. How many people use the server?
Determines how much headroom is planned for simultaneous access.
2. Which tools do you want to run?
The most popular open-source services. Multiple selection.
3. Your recommendation
Select at least one tool above, then we'll calculate the right server.
Incl. base load (Debian + Docker) and a safety margin. Ballpark figure – imports or large libraries can draw more for short bursts. For Jellyfin/Plex, software transcoding is factored in: since netcup servers offer no hardware transcoding (iGPU/QSV/NVENC), transcoding runs purely on the CPU. If you transcode regularly or several streams at once, a root server (dedicated cores, no CPU steal) runs far more reliably than shared vCores.
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💾 Storage: when in doubt, Local Block Storage
All values are non-binding ballpark figures based on typical idle/light load. Prices incl. VAT, see the netcup recommendation for the current date.
How much RAM and CPU does a self-hosting server need?
The honest answer is: it depends on which services you run and how many people use them. A single Vaultwarden password manager runs on a few hundred megabytes of RAM. A Nextcloud for the family already wants 2 GB, and Immich with its AI image recognition or a mail server like Mailcow quickly overwhelm a small server. The calculator above does the mental arithmetic for you.
How the Serverküche calculator works
The recommendation is built in three steps – deliberately with headroom, so your server doesn't run at its limit in everyday use:
- Base load: For the operating system (Debian) and the Docker environment we set a fixed baseline of RAM and CPU – even an empty server needs something.
- Your tools: Each selected service comes with a typical RAM and CPU requirement. Depending on the chosen size (S / M / L) we add headroom for simultaneous access – more users mean more parallel load. RAM requirements are summed up; for CPU, the largest single consumer counts in full and every further service only proportionally, because services rarely all run at full load at once.
- Safety margin: A buffer is added on top of the total, so short spikes (a photo import, a video transcode, a backup run) don't bring the server to its knees. Then we pick the smallest netcup server that covers both RAM and cores.
The values are proven ballpark figures, not a guarantee. If you transcode a lot at once or manage huge libraries, plan one size larger. Conversely: you can start small and later move to a bigger plan without any trouble.
Storage: when in doubt, Local Block Storage
RAM and CPU determine how smoothly your services run – storage determines how much fits in. You should consider the two separately. The NVMe SSD included in the server is plenty for the operating system and applications. But as soon as photos, media, mail or backups grow, Local Block Storage is the simplest path: it's booked independently of the server, can be enlarged at any time and costs just a fraction per gigabyte. That way you don't have to choose an expensive large server just for the storage.
Frequently asked questions
Is a VPS enough to start with, or do I need a root server?
For the vast majority of self-hosting setups a vServer (VPS) is enough – it shares the CPU with others, but is cheap and powerful enough. A root server (RS) with dedicated cores and 99.9 % SLA pays off when many people access it at once, you transcode video continuously (Jellyfin/Plex – netcup offers no hardware transcoding, it runs purely on the CPU) or you run demanding services in production. More on the netcup recommendation.
How do I expand storage later?
Most easily via Local Block Storage: it's added independently of the server and can be enlarged at any time. That way you stay flexible with the server and only pay for storage as needed.
Can I start small and upgrade later?
Yes. You start with a small plan and move to a bigger one when needed. You take your data and containers with you – a server migration is easy to plan with Docker.
Are the calculated values guaranteed?
No, they are proven ballpark figures based on typical idle and light load including a safety margin. Video transcoding, large imports or many simultaneous users can draw significantly more power for short bursts – when in doubt, pick one size larger.