Two rolls decide every offspring's passives
First the game builds a pool: every passive skill carried by either parent, with duplicates removed. Then it makes two rolls against the same weighted table.
Roll X decides how many passives the child inherits from that pool. Roll Y decides how many passives the child should end up with overall, and only if Y is greater than X does the child receive random passives to fill the difference. Four slots is the ceiling.
| Rolled number | Chance |
|---|---|
| 1 | 40% |
| 2 | 30% |
| 3 | 20% |
| 4 | 10% |
If the inheritance roll fills all four slots, the second roll is skipped entirely.
The quirk that trips up most guides
Only the first roll decides how much room random passives get. That produces a result that looks like a bug until you see the rule:
Suppose both parents together carry 2 unique passives. The child rolls X = 4, so it inherits all 2 available, then rolls Y = 3. Because Y (3) is not greater than X (4), the child receives no random passives at all. It finishes with 2 passives even though it "rolled 3". The initial number is what counts, not the number actually inherited.
The number you actually care about
If your goal is a clean child, meaning all the parents' passives and nothing extra, this is the table that matters. It is the chance that your target set comes through unharmed:
| Unique passives across both parents | Chance of a clean child |
|---|---|
| 1 | 40% |
| 2 | 24% |
| 3 | 12% |
| 4 | 10% |
So a perfect four-passive target is roughly a one-in-ten egg, before you account for mutation, Alpha status or stat Potentials.
How many eggs should you actually plan for?
A clean four-passive child is a 10% egg, which does not mean ten eggs is enough. It means each egg has a 10% chance, and the eggs do not compound. The number that matters is the chance of at least one success across a run, which is 1 − (0.9 ^ eggs):
| Eggs hatched | Chance of at least one success | Probability the run fails |
|---|---|---|
| 5 eggs | 41% | 59% |
| 10 eggs | 65% | 35% |
| 15 eggs | 79% | 21% |
| 20 eggs | 88% | 12% |
| 30 eggs | 96% | 4% |
| 50 eggs | 99% | 1% |
Every egg is one Cake, so a 30-egg run is 30 Cakes: 150 Flour, 240 Red Berries, 210 Milk, 240 Eggs and 60 Honey if you bake the standard recipe. The cakes guide has a planner for other cake types.
Four things breeders routinely get wrong
- Myth: "a better passive is harder to inherit." Inheritance is an even draw from the combined pool, and a random addition is no likelier to be tier-4 than tier-1. Only the number of passives in the pool changes your odds, never their quality.
- Myth: "4 + 0 parents are better than 2 + 2." The pool is de-duplicated before any roll, so both are identical. A clean two-passive donor is genuinely as good as a four-passive one.
- Myth: "the female parent passes more on." Neither parent is favoured: every passive has a 50/50 source split by the pool, and the only gender-sensitive rule in the game is one special combination deciding the species.
- Myth: "equipping the skill makes it pass down." For active skills the opposite is true: every skill the parent knows is eligible, equipped or not, so a high-level parent dilutes your chances.
Why 2 + 2, 3 + 1 and 4 + 0 are identical
Because the pool is de-duplicated and the rolls are made against the pool rather than against individual parents, these three distributions have exactly the same odds. That is genuinely useful: a clean two-passive donor is worth as much as a four-passive Pal when the four skills you want are spread across the pair.
- Duplicate skills on both parents neither help nor hurt, because they are discarded before the roll.
- It does not matter which parent carries which skill.
- Random passives are drawn with equal weighting by tier: a tier-4 skill is no more likely than a tier-1 when the game adds a random one.
- Skills the child actually inherited are removed from the random pool, but a parent skill it failed to inherit can still turn up as a random addition.
When parents carry more than four passives
This is where the odds collapse faster than most people expect. If the combined pool is larger than the four skills you want, the game is choosing a subset out of that pool. The probability is a binomial coefficient, not a simple ratio. Six unique passives across the parents does not give your specific four-skill set a 4-in-6 chance; it is 1 of the 15 possible four-skill subsets.
| Unique passives across both parents | Ways to pick four | Chance of your exact set |
|---|---|---|
| 4 | 1 | 10% |
| 5 | 5 | 2.0% |
| 6 | 15 | 0.67% |
| 7 | 35 | 0.29% |
| 8 | 70 | 0.14% |
This assumes the four skills you want are all present in the parents' combined pool. The practical rule that falls out of it: only ever breed pairs whose combined passive list is exactly the four you want, and nothing else.
Active skills are a separate 50% roll
Active skills do not use the passive pool at all. There is a 50% chance the child inherits one active skill from either parent, and the eligible set is every active skill the parents currently know, not just the ones equipped.
That has a counter-intuitive consequence: a heavily levelled parent carries a huge move pool, so the odds of passing down the one specific move you want get worse with the parent's level. When you breed for a move, keep the parents at a low level.
Exclusive signature skills cannot be inherited at all. There is one documented exception in the other direction: Pals that learn an exclusive move at level 1 appear to always pass on a different active skill when they do pass one, so Orserk, which learns Kerauno at level 1, will pass its other move instead of the exclusive one.
Potentials: Palworld's version of IVs
Every Pal has three hidden Potentials, ATK, DEF and HP, that determine how much of a stat it gains per level. At maximum, a Potential raises the matching stat's per-level growth by around 30%. At level 1 the difference is invisible; by the end of the level curve it is substantial, which is why two same-species Pals at the same level are not the same Pal.
Each Potential is rolled independently when an egg hatches, from exactly three sources:
| Outcome | Chance |
|---|---|
| Inherited from the father | 30% |
| Inherited from the mother | 30% |
| Randomly rerolled | 40% |
Inheriting all three Potentials from either parent is (60%)³ = 21.6%. Inheriting all three from one specific parent is (30%)³ = 2.7%.
Mutation sits on top of all of this
In Palworld 1.0, 1% of eggs are mutated, or 3% if the pair is fed an Extravagant Vegetable Cake. A mutated egg ignores part of the plan: it hatches into a much rarer Pal than the pair would normally produce, and always arrives with four passives, at least two of them tier-4, one of which is a mutation-exclusive skill. It is also Alpha, at Condensation level 2, with very high stat Potentials.
The full rules, the cake recipes and the mutation-exclusive passives are covered in the cakes guide.
A practical four-passive routine
- Fix the species first: Breed or catch the Pal you actually want before you care about passives. Rolling passives onto the wrong species wastes every egg, so check the pair in the calculator first.
- Clear the junk with same-species pairs: Same-species pairs breed true, so the species can never drift while you discard unwanted passives. Keep breeding until your two parents together carry only the skills you want.
- Stop at exactly four unique passives: Two and two, three and one, four and none: all the same odds. Every extra unique skill beyond four drops the chance of your exact set sharply, as the table above shows.
- Budget about ten eggs: A clean four-passive child is a 10% outcome, so plan ten attempts. Each attempt is one Cake, which makes passive breeding a cake-supply question as much as a strategy question.
- Check Potentials before you commit further: Once species and passives are right, the remaining variance is Potentials and the 5% Alpha roll. If you are going to keep breeding the same line, that is the point to start selecting on them.
FAQ
Do passive skills depend on the species?
No. Inheritance works identically for every pair, which is what lets you move a passive set down a breeding chain into a different species.
Should I use the Special Cake for every attempt?
Only once the species is locked in and you are rerolling passives. It raises the chance of inheriting multiple passives, and its recipe is expensive: 20 Flour, 15 Milk and 15 Eggs per cake, so it is wasted on attempts where the species is still wrong.
Can I guarantee four specific passives?
No. The best available odds are 10% per egg, and only if the two parents together carry exactly those four passives and nothing else.
Does a duplicate passive on both parents improve my odds?
No. Duplicates are discarded when the pool is built, so a skill carried by both parents counts once. Duplicates neither help nor hurt.
Does it matter which parent carries which passive?
No. A 2 + 2 split, a 3 + 1 split and a 4 + 0 split all give identical odds. Only the combined, de-duplicated list matters.
Why does the child sometimes lose a passive I know a parent had?
The inheritance roll only takes a subset of the pool. A skill that is not inherited still sits in the random pool though, so it can reappear as a random addition, which is why a "lost" passive unexpectedly shows up later.
Does Palworld 1.0 have individual stat rolls?
Yes: three of them, called Potentials (ATK, DEF, HP). Each is independently 30% from the father, 30% from the mother and 40% randomly rerolled, and a maximum Potential adds roughly 30% to that stat's per-level growth.