diff --git a/mystical-upgrader.lua b/mystical-upgrader.lua
index 277ce3c..328dd08 100644
--- a/mystical-upgrader.lua
+++ b/mystical-upgrader.lua
@@ -42,7 +42,7 @@ local assertEnoughFillBlocks = function()
 end
 
 local assertEnoughFuel = function()
-  local minFuel = 10 + (MAX_LEVEL * 2)
+  local minFuel = 10 + NB_ROWS + (MAX_LEVEL * 2 * NB_ROWS)
 
   if turtle.getFuelLevel() < minFuel then
     error('Not enough fuel')