1. Your animals
Write visual morphs plainly (Pastel, Clown), a Super form as Super Pastel, a proven recessive carrier as het Albino, and an unproven one with its chance, 66% het Clown. Leave the part after the bar empty for a normal.
2. What each outcome sells for
3. The clutch
Gene table (edit to add your own morphs)
R recessive · I incomplete dominant (a double copy is the Super form) · D dominant · L dominant that is lethal when doubled. Genes in the same group sit at the same site and are not modelled together.
Add your animals and prices, then click Rank the pairings.
Pairings, best first
| # | Female | Male | Hatchlings | Net revenue | Profit / clutch | Target chance |
|---|
Offspring odds
| Offspring | Chance per egg | Expected hatchlings | Price | Net revenue | At least one in the clutch |
|---|
How it works
Odds: every gene is its own site and is inherited independently. For each gene the planner works out the chance an egg gets zero, one or two copies from the two parents (a possible het passes the gene on with half its het chance), names the result by the gene's type, and multiplies across genes. Outcomes with the same look and the same hidden hets are merged.
Money: expected hatchlings of each outcome are eggs times hatch rate times its chance; revenue is that times its price less selling fees; profit is revenue less the raising cost per hatchling and the overhead per clutch. The chance of at least one of an outcome in a clutch is one minus the chance every egg misses.
Not modelled: genes at the same site (Lesser, Butter and Mojave, or Cinnamon and Black Pastel), which are refused; linkage; sex; infertile eggs beyond the hatch rate you enter; the price premium for a proven het; unproven hets inside a baby's name; market swings; and breeder health or welfare. Gene types follow common breeder convention and may be wrong or out of date for your line. Unverified against real clutches: the odds are checked against an independent gamete-by-gamete count and every result is re-checked for probabilities that add to one.
Common questions
Which ball python pairing should I make this season?
List your females and males with their morphs and hidden hets, add what each outcome sells for, and the planner works out the odds for every possible pairing, the expected hatchlings, the revenue after fees and raising costs, and ranks the pairings by expected profit per clutch. It uses standard Mendelian odds for each gene.
How are the odds calculated?
Each gene is treated as its own independent site. A recessive gene shows with two copies and hides as a het with one, an incomplete dominant shows with one copy and makes a Super form with two, a dominant looks the same with one or two copies, and a lethal dominant such as the spider type loses the double-copy eggs. The odds for every gene are multiplied together across all the genes in the pairing.
What does 66% het mean?
A possible het is a baby from a het-by-visual or het-by-het pairing that has not been proven. The planner treats a 66% het as carrying the gene with two-in-three odds, so it passes the gene on to one third of eggs. Breeders also write 50% poss het for the baby of a visual and a normal. Enter the percentage you have.
Why does it refuse some pairings?
Some genes sit at the same site on the chromosome, such as the Lesser, Butter and Mojave group, and Cinnamon with Black Pastel. Their odds are not independent, so a pairing that mixes them is refused instead of giving a wrong answer. Pair those animals by checking the breeder who produced the line.
Can I add my own morphs?
Yes. The gene table is editable text: name, then R for recessive, I for incomplete dominant, D for dominant or L for dominant that is lethal when doubled, then optional aliases and an optional allelic group. Check each gene's inheritance with the breeder or project that produced it before you rely on it.
Are the prices real?
No. The prices in the starter list are made-up examples. Enter what you actually sell each morph for. Any outcome you did not price uses the default price, and the planner tells you how much of the clutch fell into unpriced morphs.
Is my collection uploaded or stored?
No. Everything runs in your browser, nothing is sent to a server, there are no accounts, and nothing is saved when you close the page. Download the ranking as a CSV to keep it.