OSRS Barrows Chest Calculator
Barrows loot scales with the brothers you kill. Enter your run and chest count for the chance of any Barrows item, a specific piece, and the loot you should expect.
Killing more brothers adds rolls and improves the odds per roll.
Your planned (or past) number of chest runs.
How to use the Barrows calculator
- Set how many brothers you kill per run (all 6 is the norm).
- Enter how many chests you've done or plan to do.
- Read your chance of any Barrows item, and of one named piece like Dharok's helm.
How Barrows loot works
Every chest makes one roll at the reward table plus one more per brother killed, up to
seven. Each roll produces a Barrows item with probability
P = 1 / (450 - 58 x brothers), so a full clear rolls 7 times at 1/102 each.
There are 24 equipment pieces, and a piece already rolled in the same chest can't repeat.
At a full 6-brother clear that works out to about 1/15 chests for any Barrows item and about 1/350 chests for one specific piece like Dharok's greataxe. Over 100 chests you'll average about 6.9 items, with roughly a 25% chance at any given single piece. These figures (and our whole table) reproduce the OSRS Wiki's own worked examples, last checked 2026-09-30.
Reward potential (the combat levels you slay in the crypts) decides runes and coins, not equipment odds. Runes unlock by potential tier, and the Morytania Hard Diary boosts rune quantities by 50%.
Frequently asked questions
Does reward potential affect Barrows equipment odds?
No. The 1/(450 - 58 x brothers) roll and the 24-piece selection are the same at any potential. Potential only gates which runes, coins and bolt racks you can receive.
Can a chest give multiple Barrows items?
Yes. Each of the up-to-7 rolls can hit, so a lucky chest can hand over several pieces; on a full clear you average 0.69 items per chest (7/102).
Do I need to kill a specific brother to get his items?
Yes: his equipment can only appear if he was among the brothers you killed that run. The odds shown assume you kill the same brothers every run.
How many chests for a full collection log?
The wiki's worked math puts completing all 6 sets at about 1,319 chests on average, and a single specific set (4 pieces) at about 728. Use the calculator above to check your progress against any chest count.
Is this better than the drop chance calculator for Barrows?
Yes, for Barrows specifically. Barrows uses scaling rolls rather than one flat rate, which our drop chance calculator deliberately doesn't model. This page implements the real mechanic.
Related calculators
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Built and maintained by the OSRSCalc founder · Drop rates verified against the official OSRS Wiki on 2026-09-30 · Page last updated 2026-09-30
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