Method 1: Crafting Table
Place 3 Granite in a Crafting Table to make 6 Granite Slabs.
6 How to Make a Granite Slab in Minecraft
Use this simple recipe to make a Granite Slab in Minecraft. You can see the exact ingredients, recipe layout, and workstation below.
Granite Slab recipe
Follow the recipe below. The pattern must use the correct slots when the recipe is shaped.
6 
Method 2: Stonecutter
Use 1 Granite in a Stonecutter to make 2 Granite Slabs.
2 About this Minecraft recipe
This page shows the vanilla recipe for Granite Slab. It includes the exact ingredients, recipe layout, required workstation, and amount produced.
The data comes from Minecraft Java 26.2. Recipes can change in later game versions, so check the version you play before crafting.