Areas and levels

Twenty-four floors, four difficulties, one continuous ladder from 1 to 96. The area level is the number that decides what a place can drop and how good the rolls may be.

The ladder

area level = floor + 24 x difficulty

Six areas of four floors each: Cathedral 1-4, Catacombs 5-8, Caves 9-12, Hell 13-16, Nest 17-20, Crypt 21-24 - then the same six again, one difficulty deeper.

#	Difficulty	Area	Floors	Area level	Base tier	Opens

Hell/Hell is the design target. At area levels 61-64 the last base item becomes available, so every piece of gear in the game is obtainable by then. The eight areas past it exist for better rolls and deeper tiers, not for new things.

What the area level drives

Monster loot level - the area level, +3 for a unique, +2 for a champion.
Chests, floor spawns and quest rewards - the area level directly.
Gold piles - the amount scales with it.
Vendor stock - separately: the vendor's own level, lifted by the difficulty block.

Two things it fixed

The old floor number ignored difficulty entirely, so a chest in Torment held the same grade of loot as a chest in Normal. And Hellfire's own arithmetic folded the Nest back to floors 9-12 and the Crypt to 14-17, because in Hellfire those are a parallel path to the Cathedral rather than a deeper one. In this build they are floors 17-24 and they are deeper, so the ladder uses the floor as it is.

Quest lairs

The Skeleton King's lair, the Bone Chamber, the Poisoned Water Supply and the Vile Betrayer's chamber take the level of the quest that owns them, run through the same ladder - so a lair is as deep as the floor it hangs off, on every difficulty. An unrecognised set-level falls back to floor 1, the least rewarding answer on the ladder.

Town

Town has an area level like anywhere else, but nothing drops there, so the automap does not print one. Shops use their own level, described in Base tiers.