Ball Python Morph Calculator

Pick the genes for each parent, or use your own ball pythons, and the calculator lists every baby the pairing can produce as an exact fraction per egg. It names the combinations our references agree on, shows het odds for babies that look normal, and flags reported health problems with their sources. When the genetics are not settled, it says so instead of guessing.

How ball python genes pass to the babies

A few rules explain almost every clutch.

• Each parent passes one copy of each gene
• Recessive genes need two copies to show
• A het carries one hidden copy
• Incomplete dominant genes show with one copy
• Two copies make the super form
• Dominant genes look alike with one or two copies
• Genes in one complex share a single spot
• A snake holds at most two genes from one complex
• Mojave plus Lesser makes a Blue-Eyed Leucistic
• Possible het odds come from the parents

What the calculator will not guess

These are left out of the odds, with the reason shown.

• Banana and Coral Glow, which pass differently to sons and daughters
• Genes whose inheritance is disputed
• Genes only one reference describes
• Axanthic without a named line
• Genes that may share a complex in one parent
• Health beyond the reported, sourced notes

Frequently asked questions

How does a ball python morph calculator work?

Each parent passes one copy of every gene to each baby, chosen at random. The calculator lists every combination of copies the two parents can pass, adds up the chances, and names each result using reviewed naming rules. The odds are per egg, so a real clutch can come out differently.

What does 66% possible het mean?

When two hets are paired, two out of three of the normal-looking babies carry the gene, so breeders call each normal-looking baby a 66% possible het. If you enter a possible het based on pedigree odds, the calculator uses the figure you give as stated. If the figure comes from elsewhere, it shows both outcomes side by side instead of averaging them.

Why does the calculator leave out Banana?

Banana sits on the sex chromosomes in a way that is not fully settled, so a male Banana tends to pass it mostly to sons or mostly to daughters depending on which parent he got it from. Predicting that needs the baby's sex and the father's history, which this version does not model, so Banana is listed as not included rather than guessed.

Can two normal-looking ball pythons produce an albino?

Yes, if both carry one hidden copy of albino. Each egg then has a 1 in 4 chance of being albino, a 1 in 2 chance of being a het like the parents, and a 1 in 4 chance of carrying no albino at all.

Why are some Spider and Champagne pairings flagged?

Spider, Champagne and several related genes are linked to a neurological wobble, and two copies of Spider or Champagne are reported to be lethal. The calculator still shows those babies at conception, with the warning and its source, because leaving them out would make the other odds look better than they are.

Does a result tell me my snake's genetics?

No. A result is a prediction from the genes you enter. Saving it never changes any animal's recorded genetics, and only breeding results or a test can confirm what a snake carries.

Sources

• MorphMarket Morphpedia: ball pythons
• World of Ball Pythons: morph list
• Brown et al. 2022, PLOS ONE: albino variants
• Dao et al. 2023, G3: Yellow Belly complex
• Mallery and Carrillo 2016, Phyllomedusa: Banana and sex linkage