diff --git a/src/inventory.h b/src/inventory.h
index a690eb5ae29d825b4635888d23d1a0aa407fb738..7d7e58d610d9f5ae48ce7d65dd208748f07022d1 100644
--- a/src/inventory.h
+++ b/src/inventory.h
@@ -80,15 +80,14 @@ struct ItemStack
 	// Maximum size of a stack
 	u16 getStackMax(IItemDefManager *itemdef) const
 	{
-		s16 max = itemdef->get(name).stack_max;
-		return (max >= 0) ? max : 0;
+		return itemdef->get(name).stack_max;
 	}
 
 	// Number of items that can be added to this stack
 	u16 freeSpace(IItemDefManager *itemdef) const
 	{
 		u16 max = getStackMax(itemdef);
-		if(count > max)
+		if (count >= max)
 			return 0;
 		return max - count;
 	}
diff --git a/src/itemdef.h b/src/itemdef.h
index b14ed41f7f2a5a0b21acea8a436c98db4f454585..dcb98e8a945d01c49e2e3bb1010d6493516765ab 100644
--- a/src/itemdef.h
+++ b/src/itemdef.h
@@ -61,7 +61,7 @@ struct ItemDefinition
 	/*
 		Item stack and interaction properties
 	*/
-	s16 stack_max;
+	u16 stack_max;
 	bool usable;
 	bool liquids_pointable;
 	// May be NULL. If non-NULL, deleted by destructor
diff --git a/src/script/common/c_content.cpp b/src/script/common/c_content.cpp
index c664101eaba6825acd21251a1cdb55fe9b91f6af..19873abc552e5d5c92199c4db34497579fd04571 100644
--- a/src/script/common/c_content.cpp
+++ b/src/script/common/c_content.cpp
@@ -65,9 +65,8 @@ ItemDefinition read_item_definition(lua_State* L,int index,
 	}
 	lua_pop(L, 1);
 
-	def.stack_max = getintfield_default(L, index, "stack_max", def.stack_max);
-	if(def.stack_max == 0)
-		def.stack_max = 1;
+	int stack_max = getintfield_default(L, index, "stack_max", def.stack_max);
+	def.stack_max = rangelim(stack_max, 1, U16_MAX);
 
 	lua_getfield(L, index, "on_use");
 	def.usable = lua_isfunction(L, -1);