HOW WE CHECK

Every number on this site is read out of the game files themselves, not copied from a wiki. This page says which files, from which version, and what each one can and cannot tell you. The last read was on 2026-08-08, against Java 26.2 and Bedrock v1.26.30.5.

The reader runs again every week and compares its output with what is on the site. If a game update moves a weight or adds a drop, that shows up as a difference instead of quietly sitting there as a wrong number.

Which biome a mob spawns in, with what weight and in what group size

data/minecraft/worldgen/biome/*.json in the Java 26.2 client jar

Every biome file lists its spawners per category with a weight. The share on our pages is that weight divided by the total of its category in that biome, and nothing else: it does not say how often you meet the mob, because light, height and the mob cap decide that too. 725 entries read across 47 mobs.

Structures that impose their own spawn list

data/minecraft/worldgen/structure/*.json in the Java 26.2 client jar

A fortress, a monument or an outpost replaces the biome list inside its own walls through spawn_overrides. 9 of our mobs have such an entry, and 5 of them spawn nowhere else.

What a mob drops, how many, and with what chance

data/minecraft/loot_table/entities/*.json in the Java 26.2 client jar

109 rows across 55 mobs. What a mob carries in its hands is not in there, because equipment has its own chance; those rows come from our own data and are marked as equipment on the page.

Health, armour, knockback resistance, speed, follow range and experience

net/minecraft/world/entity/**.class in the Java 26.2 client jar, read with javap

These are not data files, they are code. Each mob class has a method that builds its attributes, and a mob without its own value inherits its parent's, so the chain is followed up to the defaults in the Attributes class. 7 mobs roll their health when they spawn instead of having a fixed value; those show a range with the method that decides it.

What Bedrock does differently

behavior_pack/spawn_rules, /entities and /loot_tables/entities in Mojang's bedrock-samples v1.26.30.5

This site describes Java. Bedrock is here as a second edition and is never used to prove a Java number, because a match there says nothing about Java. 76 of our 76 mobs have a file in the sample data, and 33 of them differ from Java on something this site shows. Bedrock sets one default weight with a biome tag where Java sets a weight per biome, so the comparison uses the weight that occurs most across Java's biome list and says so when it varies.

What we deliberately do not claim

Attack damage per difficulty. The attribute is in the jar, but a mob that swings an axe, shoots an arrow or rolls its own damage does not use it directly. Deriving a damage number from the attribute alone would be wrong for the iron golem, the vindicator and every archer, so the pages show the attribute as an attribute and the damage figures stay where they came from.
Behaviour. How a mob acts lives in code as a list of goals, and for less than half of our mobs that list is its own; the rest inherit a list that is identical for the cow, the pig and the sheep. Presenting that as a fact about one mob would say nothing, so the behaviour text stays written by hand and is not dressed up as a file reading.
Anything with the word roughly in it. The one calculation on this site that is not literally in a file is the average drop per kill, and it is only done where it is exact: every entity loot pool rolls once and every count is uniform or fixed, so chance times the middle of the count is a real average. Rows that depend on a situation are left out and counted on the page.