Cat Coat & Genetics Calculator: What Color Will Your Kittens Be?

O = orange pigment, o = non-orange pigment

The Orange locus sits on the X chromosome. Males inherit one X from the mother, so they are either orange or non-orange. Females inherit one X from each parent, so O/o females can show tortoiseshell patterning through random X-inactivation.

This is why tortoiseshell results should appear in female kittens only in normal XY/XX inheritance.

A = agouti/tabby base, a = solid when aa

Agouti controls whether banded hairs reveal a tabby ground pattern. A single A can allow tabby expression, while aa generally creates a solid coat unless orange overrides visible tabby markings.

Orange cats often show tabby markings even when solid logic would hide them.

B > b > bl

The Brown locus changes eumelanin from black to chocolate or cinnamon. B is dominant; chocolate appears when no B is present and b is present; cinnamon appears with bl/bl.

Dilution can turn black to blue, chocolate to lilac, and cinnamon to fawn.

D = dense pigment, d = dilute when dd

A cat must inherit two dilute alleles, dd, to lighten the coat. This turns black into blue, chocolate into lilac, cinnamon into fawn, and orange into cream.

A non-dilute cat can still carry dilute as Dd and pass it to kittens.

C > cb > cs > c

The Colorpoint locus affects temperature-sensitive pigment. Full-color C usually masks point expression, while cs/cs creates Siamese-style points and cb/cs creates mink.

Pointed cats can still carry the same base colors; the pattern changes where color appears.

W = dominant white, w = non-white

Dominant white can mask the underlying color and pattern. The calculator keeps the hidden genetics in the cross but reports dominant white when W is inherited.

White is a mask, so a white cat can genetically carry orange, tabby, dilute, or colorpoint.

S = white spotting, s = no spotting

White spotting has variable expression and a rough dosage effect. SS tends to show more white than Ss, while ss usually has no white spotting.

Spotting modifies the reported color, producing locket, bicolor, harlequin, or van-style labels.

Mc = mackerel, mc/mc = classic

The Mc locus changes the tabby layout when agouti permits tabby expression. Mc produces mackerel stripes, while mc/mc produces classic swirls.

Pattern is visible only when the coat is tabby or orange-based.

I = silver or smoke effect, i = normal pigment

The inhibitor gene reduces pigment along the hair shaft. On tabbies it can create silver tabby effects; on solid cats it can create smoke effects.

Silver changes presentation but usually does not change the underlying base color probability.

L = short hair, l/l = long hair

Long hair is recessive. A short-haired cat may carry long hair as Ll, but kittens need ll to show a long coat.

The calculator reports long fur as a result modifier alongside color and pattern.