Select alleles for each parent to predict offspring outcomes.
het (heterozygous) means your animal carries one copy of the gene but may not visually express it. hom (homozygous) means it carries two copies and the trait is visually expressed. Not sure what your animal is? See inheritance patterns for Corn Snake.
Don't see your morph? Join our Discord community to request it is added.
Hypomelanistic + Caramel
Charcoal (Anerythristic Type B) + Diffused (Bloodred) + Amelanistic (Albino) / Ultra
Amelanistic (Albino) / Ultra + Caramel
Amelanistic (Albino) / Ultra + Hypomelanistic
Hypomelanistic + Anerythristic Type A
Lava + Anerythristic Type A
Amelanistic (Albino) / Ultra + Lavender
Charcoal (Anerythristic Type B) + Diffused (Bloodred)
Amelanistic (Albino) / Ultra + Anerythristic Type A
Amelanistic (Albino) / Ultra + Anerythristic Type A + Motley / Stripe
Amelanistic (Albino) / Ultra + Anerythristic Type A + Motley / Stripe
Sunkissed + Anerythristic Type A
Hypomelanistic + Caramel
Charcoal (Anerythristic Type B) + Diffused (Bloodred) + Amelanistic (Albino) / Ultra
Amelanistic (Albino) / Ultra + Caramel
Amelanistic (Albino) / Ultra + Hypomelanistic
Hypomelanistic + Anerythristic Type A
Lava + Anerythristic Type A
Amelanistic (Albino) / Ultra + Lavender
Charcoal (Anerythristic Type B) + Diffused (Bloodred)
Amelanistic (Albino) / Ultra + Anerythristic Type A
Amelanistic (Albino) / Ultra + Anerythristic Type A + Motley / Stripe
Amelanistic (Albino) / Ultra + Anerythristic Type A + Motley / Stripe
Sunkissed + Anerythristic Type A
Track your animals, breeding records, weights, and more.
A look at the math behind the predictions, where the genetic data comes from, and how to report anything that looks off.
Each trait locus is treated independently. For every locus where at least one parent carries an allele, the engine enumerates the full Punnett square and computes zygosity probabilities for each possible offspring genotype.
Multi-trait outcomes are the Cartesian product of those per-locus probabilities. A Sunglow (homozygous Albino + homozygous Hypo) from two double-het parents, for example, is 25% x 25% = 6.25%.
Incomplete dominant alleles produce three distinct visual phenotypes: het (single copy), super (homozygous), and wild-type (absent). Lethal homozygous combinations are flagged and their probability is excluded from the totals. All output percentages sum to 100%.
Allele data, locus assignments, dominance patterns, and lethal pair relationships are sourced from the ReptiDex Corn Snake morph library. Every morph in the library has a documented gene locus, inheritance mode, and known co-dominant or recessive pairings.
Combo morphs (named multi-locus phenotypes like Sunglow or Banana Cinnamon) are defined by the allele combinations required to express them. When a predicted offspring genotype matches all required loci, the calculator surfaces the combo name alongside the base probability.
Reptile genetics is an active field. New morphs are identified, locus assignments are revised, and allelic relationships are updated as the breeding community accumulates proof crosses. Our morph library is updated regularly, but it may not always reflect the latest findings.
If you spot an incorrect locus assignment, a missing morph, or a prediction that does not match established proof cross data, please let us know: