Guide:Analysis of unique item tiers
This is a guide on the subject of analysing unique item drop rate tiers.
Last updated on June 5, 2025.
Any data regarding unique tiers is based on black box testing and estimates from data analysis by members of the Prohibited Library community; actual tiers may differ. Tiers may also be subject to change between patches without warning.
This page contains a list of approximate unique item tiers for the purposes of item drops and Unique item gambling. This guide only covers drop-anywhere unique items as drop-restricted uniques use different systems for their relative drop rates.
Testing was done via Ritual prices, relative trade data, and published material from GGG.
Tier distributions
When a unique item is generated, the probability that a specific unique item will be generated is weighted by a tiering system that causes certain uniques to be less or more likely to appear than others. Colloquially we call these Tiers "common" (worst, e.g. 
HoghuntHoghunt
Felled GreatclubTwo Hand Mace
Physical Damage: 13-18
Critical Strike Chance: 5.00%
Attacks per Second: 1.10
Weapon Range: 1.3 metresAdds (16-20) to (23-27) Physical Damage
+15% to Critical Hit Chance
10% reduced Attack Speed
+10 to Strength
Maim on Critical HitThere was a very clear and delicious
reason why the Ezomytes chose to
stop their flight and settle in Phaaryl.
), "uncommon", "rare", or "mythic" (best, e.g. 
AstramentisAstramentis
Stellar AmuletRequires Level 24+(5-7) to all Attributes+(50-100) to all Attributes
-4 Physical Damage taken from Attack HitsMindless rage will shake the world,
Cunning lies will bend it.
Reckless haste will break the world,
And into darkness send it.
).
Natural drops
When an item is dropped from a Monster, its rarity is determined first. If an item is determined to drop as a Unique rarity item, it will then select an eligible unique tier. The chance of uncommon, rare, or mythic tiers being selected increase as item rarity increases, while common uniques are less likely to be selected. Once the tier is selected, an eligible unique item of that tier is selected. (Eligibility may be determined by restrictions such as drop level). If no items exist for that tier, an item will be selected from the next lowest tier. An individual unique item's drop chance depends on the number eligibility of other unique items in that tier, and gets diluted as additional unique items are added to the core drop pool.[1]
It should be noted that it is currently unknown if the individual drop weights of uniques within the same tier are the same.
Currency outcomes
Orb of ChanceOrb of ChanceStack Size: 10Unpredictably either upgrades a Normal item to Unique rarity or destroys itRight click this item then left click a normal item to apply it.
: The orb chooses a unique item tier, and if a unique of that tier exists, it will upgrade upgrade into one of them at random. If a tier is rolled for which there are no eligible outcomes, a unique item will not be produced and the item will be destroyed. It will not re-attempt to generate an outcome of a lower tier. Orb of Chance respects drop levels for eligibility of a unique outcome.
Testing methodology
Early Access
After the end of Ultimatum league, as Inscribed Ultimatums were removed, it was discovered in version 3.21.0 that Rituals discretely categorized most unique items between tier 2-5 in separated tiers. Since each tier has its own ranges of ritual devotion cost, the cost of an item can be used to surmise the tier of unique items.
| Devotion cost |
Unique item tier |
|---|---|
| 1-768? | Common |
| 920-2580? | Uncommon |
| 13400-18600? | Rare |
| 22000+? | Mythic |
List of unique items by tier
Mythic: Astramentis, Mjolner, Lioneye's Glare, The Last Lament, The Whispering Ice, Cadiro's Gambit