Breeder Tools

Free, practical tools to help you plan litters and run your cattery — built by a GCCF breeder, cat judge and feline behaviourist, not a software firm. Tap any live tool below; the rest are on the way.

A breeding calculator for every stage of a litter

Most “cat breeding calculator” searches are really after one specific answer — what colour the kittens will be, when she is due, when they can leave. The tools on this page cover the whole arc, so you are not stitching together half a dozen websites written for dogs. Everything here uses GCCF colour names and GCCF timelines, because that is the world Siamese and Oriental breeders actually register into. Here is the order I use them in myself.

1. Settle your prefix first. At the start of a breeding programme, the Cattery Prefix Generator helps you brainstorm something distinctive before you apply to the GCCF — a prefix is yours for life, so it is worth getting right rather than settling under deadline pressure.

2. Plan the colours before you plan the mating. This is the step new breeders skip and regret. Run the pairing through the Siamese Colour Predictor to see every possible kitten colour and the odds, in the same colour names you will register. It will not tell you which individual kittens you will get — genetics does not work like that — but it tells you what is possible, and it stops surprises like a hidden dilute or an unexpected tortie. If the results do not make sense, the Siamese colour genetics guide explains the genes underneath them.

3. Work the dates. Once she is mated, the Litter Planner turns the mating date into a due date, a vaccination window, and the earliest day the kittens can leave — 13 weeks under the GCCF code, not the 8 you will see quoted elsewhere.

4. Track growth from day one. Daily kitten weights are the single best early-warning system a breeder has: a kitten that stops gaining is a kitten in trouble, often a day before anything else shows. The Weight Tracker (coming soon) charts each kitten so you spot the flat line early.

5. Keep the health calendar straight. The Worming & Vaccination Scheduler (coming soon) takes the birth date and gives you the full worming, vaccination and microchip calendar, so nothing slips while you have a nursery full of kittens.

Built for responsible, GCCF-registered breeding

These are planning aids, not shortcuts. Good breeding still comes down to health testing, temperament, honest matches and knowing your lines — the things a calculator cannot do for you. If you want the reasoning behind any of it, the breeding section covers stud work, pregnancy and rearing in depth.

When you outgrow spreadsheets, Perfect Pedigrees — our flagship software — handles full pedigrees, breeding records and inbreeding (COI) checks across your whole cattery. Join the waitlist above.

Frequently asked questions

Is the cat colour calculator accurate?

It shows every genetically possible colour for a pairing and the expected ratios, using standard feline colour inheritance. Ratios are probabilities across a litter, not a guarantee for any single kitten — real litters are small samples, so actual results vary.

Do I need to know genetics to use these tools?

No. Enter what you know about each parent and the tools do the work. If you want to understand the “why”, each result links through to the genetics guide.

Are the tools free?

Yes — the live tools are free to use. Perfect Pedigrees, our separate pedigree software, is free to build with — you only pay when you print a certificate.