diff --git a/api.lua b/api.lua
index 3513177..1008843 100644
--- a/api.lua
+++ b/api.lua
@@ -57,38 +57,3 @@ function microexpansion.register_item(itemstring, def)
     register_recipe(BASENAME..":"..itemstring, def.recipe)
   end
 end
-
--- [function] register cell
-function microexpansion.register_cell(itemstring, def)
-  if not def.inventory_image then
-    def.inventory_image = itemstring
-  end
-
-  -- register craftitem
-  minetest.register_craftitem(BASENAME..":"..itemstring, {
-    description = def.description,
-    inventory_image = BASENAME.."_"..def.inventory_image..".png",
-    groups = {microexpansion_cell = 1},
-    microexpansion = {
-      drive = {
-        capacity = def.capacity or 5000,
-      },
-    },
-  })
-
-  -- if recipe, register recipe
-  if def.recipe then
-    -- if recipe, register recipe
-    if def.recipe then
-      register_recipe(BASENAME..":"..itemstring, def.recipe)
-    end
-  end
-end
-
--- [function] Get cell size
-function microexpansion.get_cell_size(name)
-  local item = minetest.registered_craftitems[name]
-  if item then
-    return item.microexpansion.drive.capacity
-  end
-end
diff --git a/modules/storage/api.lua b/modules/storage/api.lua
new file mode 100644
index 0000000..b158583
--- /dev/null
+++ b/modules/storage/api.lua
@@ -0,0 +1,48 @@
+-- storage/api.lua
+
+local BASENAME = "microexpansion"
+
+-- [function] register cell
+function microexpansion.register_cell(itemstring, def)
+  if not def.inventory_image then
+    def.inventory_image = itemstring
+  end
+
+  -- register craftitem
+  minetest.register_craftitem(BASENAME..":"..itemstring, {
+    description = def.description,
+    inventory_image = BASENAME.."_"..def.inventory_image..".png",
+    groups = {microexpansion_cell = 1},
+    microexpansion = {
+      drive = {
+        capacity = def.capacity or 5000,
+      },
+    },
+  })
+
+  -- if recipe, register recipe
+  if def.recipe then
+    -- if recipe, register recipe
+    if def.recipe then
+      register_recipe(BASENAME..":"..itemstring, def.recipe)
+    end
+  end
+end
+
+-- [function] Get cell size
+function microexpansion.get_cell_size(name)
+  local item = minetest.registered_craftitems[name]
+  if item then
+    return item.microexpansion.drive.capacity
+  end
+end
+
+-- [function] Calculate max stacks
+function microexpansion.int_to_stacks(int)
+  return math.floor(int / 99)
+end
+
+-- [function] Calculate number of pages
+function microexpansion.int_to_pagenum(int)
+  return math.floor(microexpansion.int_to_stacks(int) / 32)
+end
diff --git a/modules/storage/init.lua b/modules/storage/init.lua
index c43490b..58f5052 100644
--- a/modules/storage/init.lua
+++ b/modules/storage/init.lua
@@ -2,6 +2,9 @@
 
 local module_path = microexpansion.get_module_path("storage")
 
+-- Load API
+dofile(module_path.."/api.lua")
+
 -- Load storage devices
 dofile(module_path.."/storage.lua")
 
diff --git a/modules/storage/machines.lua b/modules/storage/machines.lua
index 1ce3646..34a9af1 100644
--- a/modules/storage/machines.lua
+++ b/modules/storage/machines.lua
@@ -1,5 +1,7 @@
 -- microexpansion/machines.lua
 
+local me = microexpansion
+
 -- [me chest] Get formspec
 local function chest_formspec(start_id, listname, page_max, query)
 	local list
@@ -14,24 +16,28 @@ local function chest_formspec(start_id, listname, page_max, query)
 		page_number = "label[6.05,4.5;" .. math.floor((start_id / 32)) + 1 ..
 			"/" .. page_max .."]"
 	end
-	return "size[9,10]" ..
-	microexpansion.gui_bg ..
-	microexpansion.gui_slots ..
-	list ..
-	"list[current_name;cells;8,1.8;1,1;]" ..
-	"list[current_player;main;0,5.5;8,1;]" ..
-	"list[current_player;main;0,6.73;8,3;8]" ..
-	"button[5.4,4.35;0.8,0.9;prev;<]" ..
-	"button[7.25,4.35;0.8,0.9;next;>]" ..
-	"field[0.3,4.6;2.2,1;filter;;" .. query .. "]" ..
-	"button[2.1,4.5;0.8,0.5;search;?]" ..
-	"button[2.75,4.5;0.8,0.5;clear;X]" ..
-	"tooltip[search;Search]" ..
-	"tooltip[clear;Reset]" ..
-	"listring[current_name;main]" ..
-	"listring[current_player;main]" ..
-	"field_close_on_enter[filter;false]" ..
-	page_number
+	return [[
+		size[9,10]
+	]]..
+		microexpansion.gui_bg ..
+		microexpansion.gui_slots ..
+		list ..
+	[[
+		list[current_name;cells;8,1.8;1,1;]
+		list[current_player;main;0,5.5;8,1;]
+		list[current_player;main;0,6.73;8,3;8]
+		button[5.4,4.35;0.8,0.9;prev;<]
+		button[7.25,4.35;0.8,0.9;next;>]
+		field[0.3,4.6;2.2,1;filter;;]]..query..[[]
+		button[2.1,4.5;0.8,0.5;search;?]
+		button[2.75,4.5;0.8,0.5;clear;X]
+		tooltip[search;Search]
+		tooltip[clear;Reset]
+		listring[current_name;main]
+		listring[current_player;main]
+		field_close_on_enter[filter;false]
+	]]..
+		page_number
 end
 
 -- [me chest] Register node
@@ -85,9 +91,9 @@ minetest.register_node("microexpansion:chest", {
 			local meta = minetest.get_meta(pos)
 			local inv = meta:get_inventory()
 			local items = minetest.deserialize(stack:get_meta():get_string("items"))
-			local size = microexpansion.get_cell_size(stack:get_name())
-			local page_max = math.floor(size / 32) + 1
-			inv:set_size("main", size)
+			local size = me.get_cell_size(stack:get_name())
+			local page_max = me.int_to_pagenum(size) + 1
+			inv:set_size("main", me.int_to_stacks(size))
 			if items then
 				inv:set_list("main", items)
 			end