Use this Proxmox RAM calculator to work out how much memory your server needs based on your planned virtual machines, LXC containers, and storage configuration. Adjust the inputs and the calculator updates instantly, giving you a minimum RAM requirement and a recommended kit size.
Proxmox RAM Sizing Calculator
Estimate how much RAM your Proxmox server needs based on your planned workloads.
Virtual Machines
LXC Containers
Storage & Features
How to use this calculator
Start by entering the number of virtual machines and LXC containers you plan to run, along with the average RAM you intend to allocate to each. The Proxmox OS itself needs around 4 GB to run comfortably, and this is included automatically.
If you plan to use ZFS as your storage backend — which is recommended for data integrity — tick the ZFS box and enter your total storage size. ZFS uses RAM for its ARC (Adaptive Replacement Cache), which dramatically improves read performance but needs to be accounted for in your planning.
The recommended figure adds 25% headroom above the minimum and rounds up to the nearest standard kit size, giving you room to grow and protecting against workloads that use more RAM than their allocation at peak times.
For more on choosing hardware, see our guide: Best Hardware for a Proxmox Home Lab Server (UK).
