All of the genotypes in our foal coat colour calculator are shown as a pair because animals have two copies of almost all their genes. We use a space to separate the pair, while some labs use slashes or nothing at all.

For the red/black gene an uppercase E represents black pigment in the coat. A lowercase e represents red pigment. The uppercase E is dominant over the lowercase e.

Horses with an 'e e' genotype cannot produce black pigment in their coat.

The agouti and red/black gene work together to create the basic horse coat colours: chestnut, bay or brown, and black. Have a play with the calculator to see what we mean.

All of the genotypes in our foal coat colour calculator are shown as a pair because animals have two copies of almost all their genes. We use a space to separate the pair, while some labs use slashes or nothing at all.

For the agouti gene an uppercase A represents black pigment being restricted to the mane, tail and points. A lowercase a allows black pigment to cover the whole body. The uppercase A is dominant over the lowercase a.

If a horse has no black pigment the agouti gene has no visible effect on its coat colour. It can still potentially impact the colour of any foals.

The agouti and red/black gene work together to create the basic horse coat colours: chestnut, bay or brown, and black. Have a play with the calculator to see what we mean.

All of the genotypes in our foal coat colour calculator are shown as a pair because animals have two copies of almost all their genes. We use a space to separate the pair, while some labs use slashes or nothing at all.

We use a lowercase n to mean negative or normal.

Cream (shown as Cr) and pearl (shown as PRL) are caused by two different mutations in the same gene.

A single copy of cream lightens red pigment in the coat to a gold colour. When two copies of cream are present it dilutes both red and black pigment to a creamy colour, and also lightens eye pigment to a blue or green colour.

One copy of pearl by itself does not alter coat colour. However when you have two copies of pearl, or one copy of pearl and one copy of cream, both red and black pigment in the coat are diluted to a creamy colour and the eyes are also lightened. The effect is not as strong as what you see with two copies of cream.

All of the genotypes in our foal coat colour calculator are shown as a pair because animals have two copies of almost all their genes. We use a space to separate the pair, while some labs use slashes or nothing at all.

We use a lowercase n to mean negative or normal.

Dun (shown as D) and not-dun-1 (shown as nd1) are caused by two different mutations in the same gene.

One or two copies of dun lightens both red and black pigment by limiting the distribution of pigment granules to just a small part of the hair shaft. This dilution is accompanied by darker undiluted markings that can include a dorsal stripe, leg barring, dark ear tips, and shoulder bars. The face and points of dun horses are also usually darker than their bodies.

The effect of nd1 is less intense than dun but follows the same pattern. It is too subtle to show on our cartoon illustrations, but in real life it can be noticeable, particularly in foals. Horses with nd1 but not dun do not count as dun.

All of the genotypes in our foal coat colour calculator are shown as a pair because animals have two copies of almost all their genes. We use a space to separate the pair, while some labs use slashes or nothing at all.

We use a lowercase n to mean negative or normal. A champagne genotype is shown as Ch.

The champagne gene lightens or dilutes both black and red pigment in the coat. You will also see that horses and ponies with one or two copies of the champagne gene are born with blue eyes that mature to a green, hazel, or golden colour. They also have distinctive freckled-looking semipigmented skin.

All of the genotypes in our foal coat colour calculator are shown as a pair because animals have two copies of almost all their genes. We use a space to separate the pair, while some labs use slashes or nothing at all.

We use a lowercase n to mean negative or normal.

A silver genotype is shown as Z.

Black pigment is lightened to a chocolate or silvery colour for horses with one or two copies of silver. This is often more noticeable in the mane and tail. Silver does not have an effect on red pigment.

Health: Silver is associated with eye abnormalities in some but not all silver horses. This is referred to as multiple congenital ocular abnormalities (MCOA). Horses with two copies of the silver gene are substantially more likely to show signs of MCOA than those with one copy of the gene.

All of the genotypes in our foal coat colour calculator are shown as a pair because animals have two copies of almost all their genes. We use a space to separate the pair, while some labs use slashes or nothing at all.

We use a lowercase n to mean negative or normal. The grey gene is represented with Gr.

Grey horses are not grey at birth. They go grey with age. For most horses they grey is clearly visible by the time they are one or two years old, but sometimes it can take longer. In our calculator we include the birth colour in our description, for example "grey (born bay)".

Health: grey horses develop melanomas on average several years earlier than non-grey horses. Grey horses that are 'a a' at the agouti gene have the highest incidence of early melanoma.

All of the genotypes in our foal coat colour calculator are shown as a pair because animals have two copies of almost all their genes. We use a space to separate the pair, while some labs use slashes or nothing at all.

We use a lowercase n to mean negative or normal. The frame overo gene is represented with Ovr.

Frame overo markings include eye-catching white patches, and often a white face accompanied by one or two blue eyes. The amount of white on a frame overo horse or pony can be highly variable, from a couple of white hairs all the way up to majority white coat colours.

Health: frame overo is unique among white coat colour patterns in that foals born with two copies of the frame overo gene suffer from the heart-breaking fatal disorder known as Overo Lethal White Syndrome (OLWS)

All of the genotypes in our foal coat colour calculator are shown as a pair because animals have two copies of almost all their genes. We use a space to separate the pair, while some labs use slashes or nothing at all.

We use a lowercase n to mean negative or normal. The leopard complex gene is represented with Lp.

Horses with Lp can show white patterns in many different ways. Some will have a classic Appaloosa blanket with spots, but there are many other patterns too. We try to represent some of this variety by randomly showing either a spotted blanket or a varnish roan when we show a horse with one copy of Lp.

Health: horses and ponies that have two copies of Lp have a condition called Congenital Stationary Night Blindness (CSNB) as well as fewer (or no) coloured spots in the white patches of their coat.

All of the genotypes in our foal coat colour calculator are shown as a pair because animals have two copies of almost all their genes. We use a space to separate the pair, while some labs use slashes or nothing at all.

We use a lowercase n to mean negative or normal.A splashed white 1 genotype is shown as SW1 and a splashed white 3 genotype is shown as SW3. These two forms of splashed white along with others are caused by different mutations in the same gene (the MITF gene). Other forms of splashed white are caused by different mutations in the PAX3 gene.

All the splashed white genes cause white markings. They can range from minor facial markings and socks to the white face, blue eyes, white legs and white belly of a typical boldly marked splash horse. In our calculator we show fairly big splashed white markings. Two copies of splashed white genes in any combination causes larger white markings than a single splashed white gene.

Health: splashed white in all its forms is associated with deafness. The likelihood of deafness in one or both ears increases with the degree of the splashed white markings.

All of the genotypes in our foal coat colour calculator are shown as a pair because animals have two copies of almost all their genes. We use a space to separate the pair, while some labs use slashes or nothing at all.

We use a lowercase n to mean negative or normal. A splashed white 2 genotype is shown as SW2 and a splashed white 4 genotype is shown as SW4. These two forms of splashed white along with others are caused by different mutations in the same gene (the PAX3 gene). Other forms of splashed white are caused by different mutations in the MITF gene.

All the splashed white genes cause white markings. They can range from minor facial markings and socks to the white face, blue eyes, white legs and white belly of a typical boldly marked splash horse. In our calculator we show fairly big splashed white markings. Two copies of splashed white genes in any combination causes larger white markings than a single splashed white gene.

Health: splashed white in all its forms is associated with deafness. The likelihood of deafness in one or both ears increases with the degree of the splashed white markings.

All of the genotypes in our foal coat colour calculator are shown as a pair because animals have two copies of almost all their genes. We use a space to separate the pair, while some labs use slashes or nothing at all.

We use a lowercase n to mean negative or normal.

Here is a guide to the possibilities in this calculator for white markings caused by mutations in or near the KIT gene:

• Roan: Rn
• Sabino 1: SB1
• Tobiano: TO
• W20: W20
• Dominant white: WD (use this for calculations for any W gene except W20)

Remember that your horse or pony can only pass on one of these genes at a time, so for example if your horse is both roan and tobiano it will pass on either roan or tobiano, never both and never neither. Have a play with the calculator to see the effect.

For the pro: this calculor does not account for linkage between KIT gene white markings and red/black alleles.