How Much RAM Does a Project Zomboid Server Need?
In Project Zomboid, RAM is decided by your mods and map more than by how many friends you have. Here's the rule of thumb, and how to notice when you've come up short.
The rule of thumb
On Build 42, 6 GB minimum, even for a group of friends with no mods: we tested it on 4 GB and it runs with barely half a gig to spare, so any memory spike shows (why Build 42 needs more than 41). With a long list of Steam Workshop mods or extra maps, go up to 8 GB. The more items, scripts and loaded areas, the more memory the server uses, and that grows faster with mods than with each new player.
Other guides give formulas like “2 GB base plus half a gig per player and 2–4 GB for mods”; they're rough, and on Build 42 they tend to fall short at the low end. What matters is measuring it with your group. If you want a number to start with, the RAM calculator works it out from your players and your mods.
Rather not set it up yourself? Project Zomboid servers from €12 a month, no contract and a full refund within 72 hours. Or create a free Project Zomboid server, no card needed.
How to tell you're running short
The usual symptoms: stutters that get worse the longer the server has been up, memory errors in the console (OutOfMemoryError) or unexpected restarts, and long loading times when connecting. If you see those, you're short on RAM. If instead everything is in slow motion right from start-up, it's not memory but the CPU: the lag guide helps you tell them apart.
What isn't a symptom: the panel showing memory almost full. The Zomboid server runs on Java and grabs nearly all of the plan's memory up front, even with nobody playing (we measured it: on 4 GB it shows about 3.9 with no players). Watch the symptoms, not the number.
Before upgrading, try the cheap fixes: remove mods you don't use, add new ones a few at a time (how to add mods without breaking anything) and restart the server now and then.
Which NapNodes plan to choose
Fort (6 GB) for a group of friends or a steady community with Workshop mods; Bastion (8 GB) for extra maps and long mod lists. We don't sell Zomboid plans under 6 GB, and we don't let any Zomboid server go below that: on Build 42 they'd be too tight. The RAM is reserved for you, and you can try it for 72 hours with a full refund.
The RAM belongs to your account, not to one server. If it falls short, “Buy RAM” in “My servers” adds more, and “Adjust” on the server's card gives it to that server; or, in “My plan & invoices”, “More RAM” moves your plan from Fort to Bastion and you only pay the difference. It arrives on restart, with the same world and without reinstalling anything: how to give your server more RAM (in Spanish).
Frequently asked questions
Is 4 GB enough for a Project Zomboid server?
Not on Build 42: it starts, but with barely half a gig to spare. Use 6 GB minimum, and 8 GB with lots of mods or extra maps.
How much RAM do I need to play with mods?
6 GB with a few mods; 8 GB for a long list of Workshop mods. Add them a few at a time and watch for the symptoms. If you're looking for which ones to use, the best mods for multiplayer.
How do I give my Zomboid server more RAM?
On NapNodes, with “Buy RAM” in “My servers” and “Adjust” on the server's card, or with “More RAM” in “My plan & invoices”. The new RAM arrives on restart, with the same world.
What matters more for RAM, player count or mods?
Usually the mods and the map. Every new player adds a bit, but a long mod list tends to weigh more.
Shall we set it up for you?
Project Zomboid servers from €12 a month, never oversold: your RAM is yours alone. And if you'd rather start without paying, there's a free Project Zomboid server, no card needed.
Adding Workshop mods? Paste the links and Mod IDs into the Project Zomboid mod list tool: out come WorkshopItems= and Mods= with the Build 42 backslash.
Not sure whether your server is online? Check it in a second with the Project Zomboid server status checker: players, version and password, free.