The three rules, in priority order
Every breeding result in Palworld 1.0 comes from one of three rules. The game checks them in order and stops at the first that applies, so knowing which one your pair falls under tells you everything about the egg.
- 1. Special combinations win first: 138 hard-coded pairs produce a fixed child, and the rank maths never runs.
- 2. Same-species pairs breed true: two Pals of the same species always produce that species.
- 3. Everything else averages the parents' ranks: floor((rank A + rank B + 1) / 2) picks the eligible Pal closest to that number.
Nothing else changes the species of a normal egg: no cake, no base upgrade, no work suitability, and no gender. Gender matters in exactly two places: a Breeding Farm needs one male and one female, and one single special combination is gender-sensitive.
Step 1: Special combinations take precedence over the formula
Palworld 1.0 ships 138 fixed pairs. If your two parents are on that list, the listed child hatches no matter how their ranks line up. This is how the elemental subspecies are made: Fuack Ignis, Jolthog Cryst and Falken Cryst are not ordinary formula results, they are fixed combinations.
For a few of those Pals the special combination is not just the easiest route, it is the only one. Fuack Ignis and Jolthog Cryst each have exactly one pair in the current data: their own fixed combination, because the rank formula is not allowed to produce them as a child at all.
One combination is gender-sensitive: Katress with Wixen produces a different child depending on which parent is female. Everywhere else, parent order and gender are irrelevant, and a calculator that shows two results for Katress + Wixen is showing you both real outcomes rather than being confused.
Step 2: Same-species pairs breed true
Two Lamball always produce a Lamball, and two Anubis always produce an Anubis. Same-species breeding is the one place where the rank formula can be completely ignored, which makes it the cheapest way to reroll passive skills: the species is fixed, so the only variable left is the passive roll.
This is also the standard way to grow a working line. Catch or hatch one good specimen, then pair it with a same-species partner and keep only the offspring whose passives you want.
Step 3: Everything else is the rank average
Each Pal has a hidden breeding rank, and the game turns the two ranks into a target number, then hatches the eligible species sitting closest to it:
| Step | What the game does |
|---|---|
| 1 | Take parent A's breeding rank. |
| 2 | Take parent B's breeding rank. |
| 3 | Add them together and add 1: rank A + rank B + 1. |
| 4 | Divide by 2 and round down: floor((rank A + rank B + 1) / 2). |
| 5 | Hatch the eligible Pal whose rank is closest to that target. |
| 6 | If two Pals are equally close, the one with the lower index number wins. |
That last step is the documented tie-break rule, and it is why an exact midpoint pair can look "wrong" at first glance. It is not a bug. It is the lowest index number taking the win, and the Pal Breeding Calculator engine implements it.
A worked example you can check in the calculator
Take Anubis (rank 480) and Lamball (rank 3050). The target is (480 + 3050 + 1) / 2 = 1765.5, rounded down to 1765. The eligible Pal whose rank sits closest to 1765 is Hoodle, which is exactly what the calculator on the homepage shows for that pair, along with the target number so you can follow the arithmetic yourself.
Because the result is always an average, a child can never be rarer than its rarer parent, and never weaker than its weaker parent. Its rank always lands between the two parents' ranks, and the species that hatches is whatever occupies that slot in the table.
Why 104 Pals can never hatch from the formula
Not every Pal is a legal child. In the current data, 104 of the 299 Pals are excluded from the rank formula's candidate pool: legendaries, collab Pals and other fixed entries. They can still be used as parents, and their ranks still count in the average, but no combination of ranks will ever produce them as the child.
Those Pals reach you in three ways instead: a fixed special combination, catching them in the wild, or a multi-generation chain that ends in the right special combination. Every Pal page on Pal Breeding Calculator states which of the three applies.
Reading the numbers: rank, index and Paldeck number
The breeding rank is not the Paldeck number and the two are easy to confuse. The Paldeck number is the encyclopaedia order you see in game; the breeding rank is a separate hidden value where a lower number means a rarer, stronger Pal. In the current data the ranks run from 20 to 3100, with Lamball at 3050 at the common end, Anubis at 480 near the rare end.
There is a third value behind the scenes: the index number used only to break ties. It never appears in game, which is why the tie-break is the least predictable-looking part of the formula even though it is fully deterministic.
Why the same Pal keeps appearing from unrelated pairs
Because averaging compresses the table, popular mid-rank Pals are reachable from an enormous number of pairs. In the current data Anubis can be produced by 234 parent pairs, Katress by 447, and Felbat by 1,280, the longest list in the game.
That is useful in both directions. If you are hunting a specific Pal, the pair list is long and you probably own a workable pair already. If you are trying to breed something rare, remember that every common pair you throw at it lands on one of those mid-rank hubs instead.
When one egg is not enough: building a chain
If your target sits outside your parents' rank range, no single pair will ever reach it. The fix is to build the rank you need first:
- Find the target's rank: Open the Pal's breeding page. It states the breeding rank, how many pairs can produce it, and whether it can be bred at all.
- Pick an intermediate: Choose a Pal whose rank sits between your current parents and the target. You are not trying to hit the target yet. You are manufacturing a rank closer to it.
- Breed the intermediate: Breed your existing Pals to produce the intermediate, then check its own breeding page for the pairs that finish the job.
- Close the gap: Pair the intermediate with the parent whose rank balances the average onto the target. Repeat as often as the gap needs.
What the calculator verifies, and what it does not
A formula is only as good as the data behind it, so Pal Breeding Calculator does not take the breeding engine on trust. Every parent pair the game can produce is replayed through the WordPress engine and compared against the original algorithm: 44,851 pairs, zero mismatches, including the gender-sensitive Katress + Wixen case.
What the rank formula does not cover is everything that happens on top of the species: passive-skill inheritance, active-skill inheritance, stat Potentials, the 5% Alpha roll and the 1% mutation roll are all separate mechanics with their own odds. They are documented in the other guides rather than folded into the calculator's species prediction.
FAQ
Does parent gender change the child species?
Only for one special combination. Katress with Wixen produces a different child depending on which parent is female; every other pair in the game produces the same child regardless of gender.
Why do two completely different pairs give me the same child?
Because both pairs averaged to a rank nearest the same Pal. Hundreds of pairs can converge on one mid-rank Pal: Anubis has 234 parent pairs, Felbat has 1,280.
Can I breed a legendary Pal?
Only through a fixed special combination. Legendaries are excluded from the rank formula's candidate pool, so rank averaging can never produce one.
What does the "+ 1" in the formula actually do?
It biases the average upward by half a rank before the floor is taken. Without it, an average landing on .5 would round down and shift the whole table toward rarer Pals.
Do Cakes or base upgrades change which Pal hatches?
No. For a normal egg the species is fixed by the rules above. Cakes change egg count, mutation chance, stat growth and passive inheritance. They never change the species of a regular hatch.
Is the breeding rank the same as the Paldeck number?
No. The Paldeck number is the in-game encyclopaedia order; the breeding rank is a separate hidden value where lower means rarer. In the current data ranks run from 20 to 3100.