McStack allows you to customize the maximum stack size of any item in Minecraft - including items that normally only stack to 1, like
water bottles,
potions,
ender pearls, and more.
Unlike vanilla behavior, McStack makes it possible to:
✅ Custom stack sizes per item via config.yml
✅ Full support for potion variants (e.g. potion:water, potion:instant_heal)
✅ In-game commands to reload or update stack sizes
✅ Smart stacking behavior for shift-click and double-click
✅ ProtocolLib support to update client visuals
✅ Works out-of-the-box with Paper 1.21.3+
Example of config.yml
Commands
/mcstack reload | Reloads the plugin config.
/mcstack set <item>[:variant] <amount> | Sets max stack size for an item.
/mcstack list | Lists all configured stack overrides.
Permissions
mcstack.admin | Allows use of all McStack commands.
Tips
Using ProtocolLib is recommended for best experience - it lets clients see your custom stack sizes.
Items like POTION, SPLASH_POTION, and LINGERING_POTION support specific types using the :<variant> syntax.
Unlike vanilla behavior, McStack makes it possible to:
- Stack items like potion, splash_potion, and honey_bottle up to your own configured limits
- Shift-click to auto-stack and organize efficiently
- Double-click to collect matching items from your inventory
- Visually show clients the new stack limits (with ProtocolLib support)
✅ Custom stack sizes per item via config.yml
✅ Full support for potion variants (e.g. potion:water, potion:instant_heal)
✅ In-game commands to reload or update stack sizes
✅ Smart stacking behavior for shift-click and double-click
✅ ProtocolLib support to update client visuals
✅ Works out-of-the-box with Paper 1.21.3+
Example of config.yml
Code (YAML):
stack-sizes:
potion : 8
potion:water : 16
splash_potion:instant_heal : 4
honey_bottle : 8
ender_pearl : 16
potion : 8
potion:water : 16
splash_potion:instant_heal : 4
honey_bottle : 8
ender_pearl : 16
/mcstack reload | Reloads the plugin config.
/mcstack set <item>[:variant] <amount> | Sets max stack size for an item.
/mcstack list | Lists all configured stack overrides.
Permissions
mcstack.admin | Allows use of all McStack commands.
Tips
Using ProtocolLib is recommended for best experience - it lets clients see your custom stack sizes.
Items like POTION, SPLASH_POTION, and LINGERING_POTION support specific types using the :<variant> syntax.
Quick facts
- Edition: Minecraft Java
- File type: .jar
- Minecraft version listed: 1.21
- How to install: Install the matching mod loader (Forge, Fabric or NeoForge) for your Minecraft version. → Download the .jar. → Put it in the .minecraft/mods folder and launch that loader profile.
- Where to get it: Opens on Spigot — not every file is mirrored on our own servers.
Install steps are the general flow for this file type — How to install Minecraft Java mods & modpacks walks through it step by step.
McStack is a free Minecraft Java mod. Compatible with Minecraft 1.21. Downloaded 126 times (via Spigot). Download it and open it directly in the game.