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Project Zomboid server requirements

What a Project Zomboid server needs in CPU, memory, disk and bandwidth, by player count. Change the numbers for your own server; the sources are listed below.

Mods (Steam Workshop)
Assumptions

What it needs

CPU
5 coresSingle-thread heavy: clock speed matters more than core count.
Memory
20 GB
NVMe storage
50 GB
Traffic per month
3.6 TB
Busiest upload
32 Mbit/s

On Clouduxe

Room to grow

VDS PrimeCore

8 dedicated cores, 32 GB DDR5, 800 GB NVMe, 16 TB traffic

₹19,880$209.49/mo

  • 2 more dedicated cores, 8 GB more memory, 300 GB more NVMe.
  • Headroom for busy evenings, more players, and the mods and updates you add later.
Deploy PrimeCoreAbout PrimeCore

By player count. Without mods (steam workshop); each step up in the calculator adds memory, disk and sometimes a core.

PlayersCPUMemoryNVMeTraffic a monthFits your loadRoom to grow
42 cores6 GB50 GB454 GBVPS StarterVDS MicroCore
82 cores8 GB50 GB907 GBVPS GrowthVDS MicroCore
163 cores12 GB50 GB1.8 TBVPS ProVDS FusionCore
325 cores20 GB50 GB3.6 TBVDS OmniCoreVDS PrimeCore
649 cores35.5 GB50 GB7.3 TBVDS TitanCoreVDS UltraCore
10014 cores53 GB50 GB11 TBVDS UltraCoreBare metal

Traffic assumes 35% of the player cap online on average across the month; change it under Assumptions in the calculator.

Where the numbers come from. Published figures first, then how the calculator turns them into a model.

Published requirements

How the model is built

Memory
4 GB plus 500 MB per player. The official PZwiki startup guidance says a 1-4 player vanilla server is comfortable at 4-6 GB -Xmx, 5-8 players want around 8 GB, and heavily modded or 16-player worlds need 12-16 GB or more (source 1). Base 4 GB plus 500 MB/player reproduces this closely (6 GB at 4 players, 8 GB at 8 players, 12 GB at 16 players) and matches the 500 MB/player slope a hosting guide's own stated rule of thumb uses for Build 42 ('6GB base + 0.5GB per player', source 2), just with a lower base to match the wiki's own bracket. This is the vanilla figure; the mods multiplier scales it up for modded worlds.
CPU
2 cores, one more for every 8 players. A hosting guide's per-player table (source 3) gives 2 vCPU at 4-8 players, 4 vCPU at 16 players, and 6 vCPU at 32 players, all specifying 3.5+ GHz; another source (source 4) instead recommends a quad-core minimum regardless of player count with strong single-core performance. 2 base cores plus one extra core every 8 players matches source 3's 8 and 16 player figures closely; treat the higher quad-core-minimum guidance in source 4 as a more conservative alternative.
Disk
15 GB for the server plus 35 GB for saves and backups, on SSD or NVMe. Source 4 gives 20 GB minimum (game plus a small world) and 50 GB+ recommended (large worlds, mods, frequent saves); install (~15 GB for the game/SteamCMD) plus growth (~35 GB for world saves, backups and mods) matches that recommended figure. Source 3's own per-player table runs much higher at large player counts (40 GB at 4 players up to 160 GB at 32 players), reflecting how many map cells get saved when players spread out; busy 16-32 player worlds should budget well above the default here. SSD/NVMe is called out explicitly in both sources.
Bandwidth
1000 kbit/s of upload per player. Source 4 gives 5 Mbps upload minimum for a small private server and 20-50 Mbps upload recommended for a larger multiplayer server. Dividing those by representative player counts (about 4 for 'small private' and 16-32 for 'larger multiplayer') gives roughly 1000-1500 kbps per player in both brackets, so 1000 kbps per player is used as a defensible, slightly conservative figure. Treat as upload from the server; Build 42's server-side inventory and timed-action handling make this a chattier server than earlier builds.
Mods (Steam Workshop)
Memory times 1.3 for some and 1.8 for heavy; a heavy load also adds a core.

The official PZwiki gives concrete -Xmx memory brackets by player count, which anchors the RAM model directly; CPU, disk and bandwidth come from widely used hosting guides that broadly agree with each other and with the wiki's RAM brackets. Build 42 needs noticeably more memory than Build 41 because inventory and timed actions now run server-side; heavily modded servers, especially with large map mods, can need significantly more RAM and disk than the vanilla figures shown.

Before you set it up. The ports it listens on and what the guides say drives its load.

Ports

PortProtocolUsed for
16261UDPgame traffic / handshake (DefaultPort)
16262UDPsecondary game port (UDPPort)

Game server hosting: every game we size, the protection each one gets, and the plan for it.

DDoS protection is on every Clouduxe plan. How Prism handles game traffic.

What drives the load

  • Project Zomboid is Java-based and its -Xmx setting is a hard ceiling: the server crashes if it needs more than that, even if the machine has spare physical RAM sitting idle.
  • Leave a few GB of headroom for the OS; do not set -Xmx to the box's full physical RAM.
  • Player distribution matters more than raw player count: spread-out players load more map cells at once, raising both RAM and CPU load faster than a simple per-player count suggests.
  • The default max player count is 32; the setting can be raised up to 100 but the game's own guidance warns of poor map streaming and desync above 32.

Project Zomboid server questions

Talk to us
How much RAM does a Project Zomboid server need?

About 6 GB for 4 players and 53 GB for 100, before mods (steam workshop). The official PZwiki startup guidance says a 1-4 player vanilla server is comfortable at 4-6 GB -Xmx, 5-8 players want around 8 GB, and heavily modded or 16-player worlds need 12-16 GB or more (source 1). Base 4 GB plus 500 MB/player reproduces this closely (6 GB at 4 players, 8 GB at 8 players, 12 GB at 16 players) and matches the 500 MB/player slope a hosting guide's own stated rule of thumb uses for Build 42 ('6GB base + 0.5GB per player', source 2), just with a lower base to match the wiki's own bracket. This is the vanilla figure; the mods multiplier scales it up for modded worlds.

How many CPU cores does a Project Zomboid server need?

2 for 4 players, 14 for 100. The server is single-thread heavy, so the clock speed of one core matters more than how many cores it has. A hosting guide's per-player table (source 3) gives 2 vCPU at 4-8 players, 4 vCPU at 16 players, and 6 vCPU at 32 players, all specifying 3.5+ GHz; another source (source 4) instead recommends a quad-core minimum regardless of player count with strong single-core performance. 2 base cores plus one extra core every 8 players matches source 3's 8 and 16 player figures closely; treat the higher quad-core-minimum guidance in source 4 as a more conservative alternative.

How much bandwidth does a Project Zomboid server use?

About 1000 kbit/s of upload per connected player, so 32 Mbit/s with 32 players online and about 3.6 TB a month if 35% of that cap is online on average. Source 4 gives 5 Mbps upload minimum for a small private server and 20-50 Mbps upload recommended for a larger multiplayer server. Dividing those by representative player counts (about 4 for 'small private' and 16-32 for 'larger multiplayer') gives roughly 1000-1500 kbps per player in both brackets, so 1000 kbps per player is used as a defensible, slightly conservative figure. Treat as upload from the server; Build 42's server-side inventory and timed-action handling make this a chattier server than earlier builds.

Which Clouduxe plan should I pick for Project Zomboid?

For 32 players, VDS OmniCore fits the load and VDS PrimeCore leaves room to grow. Every plan includes DDoS protection: 17 Tbps of upstream mitigation plus Clouduxe Prism on the server.

Other games. The same calculator, sized from each game's own documentation.

All calculators

Host Project Zomboid on VDS OmniCore.

Sized for 32 players, with DDoS protection included. Or talk to us about a bigger server.

See VDS OmniCoreSize another server