British Shorthair — Color Genetics & EMS Calculator

The British Shorthair carries one of the broadest FIFe-approved color palettes in the pedigree cat world, with valid EMS codes spanning all base colors at the B locus (black, chocolate, cinnamon and their dilutes), all tabby pattern variants, colourpoint (cs) series, and the full white-spotting spectrum. Feline genetics programs for BSH must account for the high prevalence of recessive dilution (d) and chocolate (b) alleles concealed within otherwise black-phenotype animals. A robust EMS color calculator is indispensable for BSH breeders managing multi-generational carrier mapping.

British Shorthair colour genetics: frequently asked questions

Which recessive colours do British Shorthair cats commonly carry?
The British Shorthair population has a high frequency of recessive chocolate (b) carriers due to historic breeding programs. Dilution (d) is similarly widespread. Cinnamon (bl) and fawn (bl + d) are accepted and their recessive alleles persist as hidden carriers in non-cinnamon lines. Colourpoint (cs) is accepted and many non-pointed BSHs carry a single cs allele.
What colour restrictions apply to the British Shorthair breed standard?
No genetic color restrictions apply to the British Shorthair — it is one of very few breeds where all B-locus alleles (B, b, bl), the colourpoint series (C, cs), and the full O-locus expression are accepted. Dominant White (W) is permissible. The Amber (e) allele is not recognized in BSH. White-spotted (S locus) bicolors are accepted across the full van-to-any-white spectrum (01–09).
Which coat patterns are typical for the British Shorthair?
All four tabby patterns (classic 22, mackerel 23, spotted 24, ticked 25) are accepted in BSH. The British Shorthair frequently expresses the Spotted pattern (24), which is highly popular in the breed. Silver and golden series (Inhibitor locus / I) are both well-established in BSH lines. The 'tipped' (11) and 'shaded' (11) variants require careful EMS annotation to distinguish from smoke (ns series).

Popular EMS Colors

BSH aBlue (solid) — the classic British Blue
BSH n 24Black Spotted Tabby
BSH bs 24Chocolate Silver Spotted Tabby
BSH a 33Blue Colourpoint
BSH f 24Black Tortie Spotted Tabby
BSH ns 11Black Silver Shaded (Chinchilla-type)

Calculate Colors for British Shorthair

Free online cat color genetics calculator. Select the breed and appearance of the sire and dam to predict kitten coat colors, patterns and probabilities based on feline color genetics.

Sire (Father)
Dam (Mother)

Enter the appearance of both parents to calculate color predictions.

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