Holland Lop Color Calculator

Enter Parent Genotypes

Parent One Name

Parent Two Name

Expected Litter Size

Results To Show

Breeding Goal Filter

Optional Breeder Note

Parent One Agouti Series Controls agouti, tan pattern, or self grouping.

Parent Two Agouti Series Controls agouti, tan pattern, or self grouping.

Parent One Black Series Controls black or chocolate base.

Parent Two Black Series Controls black or chocolate base.

Parent One Color Series Controls full color, chinchilla, shaded, pointed, or white mask.

Parent Two Color Series Controls full color, chinchilla, shaded, pointed, or white mask.

Parent One Dilution Series Controls dense or dilute coat expression.

Parent Two Dilution Series Controls dense or dilute coat expression.

Parent One Extension Series Controls normal extension or non-extension shades.

Parent Two Extension Series Controls normal extension or non-extension shades.

Parent One Broken Pattern Controls solid, broken, or charlie pattern risk.

Parent Two Broken Pattern Controls solid, broken, or charlie pattern risk.

Parent One Vienna Series Controls blue eyed white or Vienna carrier status.

Parent Two Vienna Series Controls blue eyed white or Vienna carrier status.

Formula Used

Each locus uses a Punnett style cross. A parent with two different alleles gives each allele a 50% gamete chance. A parent with matching alleles gives that allele a 100% gamete chance.

Child genotype chance equals parent one gamete chance multiplied by parent two gamete chance. Final color chance equals the combined chance across all selected loci.

Phenotype chance is found by grouping all child genotypes that create the same visible color. This is a simplified planning model for common Holland Lop coat outcomes.

How To Use This Calculator

Enter parent names or leave the default names.
Select each known genotype for both rabbits.
Use carried genes when pedigree data supports them.
Enter an expected litter size for kit estimates.
Choose a goal filter if you want a quick match percentage.
Press the calculate button to show results above the form.
Download the table as CSV or PDF for records.

Example Data Table

Parent One	Parent Two	Important Genes	Likely Result Notes
Broken black tort	Solid blue	E/e × e/e, D/d × d/d, En/en × en/en	May produce tort, blue tort, solid, and broken kits.
Chestnut carrying chocolate	Chocolate otter	B/b × b/b, A/a × at/a	Can produce black based and chocolate based outcomes.
Vienna carrier	Vienna carrier	V/v × V/v	Can produce normal, carrier, marked, or blue eyed white kits.
REW carrier	REW carrier	C/c × C/c	Can produce full color, carriers, and ruby eyed white kits.

Understanding Holland Lop Color Planning

Holland Lop colors come from several gene groups. Each group controls a visible coat feature. The agouti series changes banding and tan markings. The black series separates black based coats from chocolate based coats. The dilution series changes black to blue, and chocolate to lilac. The extension series can create tort, orange, or related non extension shades. White masking genes can hide the color that a rabbit still carries.

Why Genotypes Matter

A visible color is not the whole story. A black Holland Lop may carry chocolate. A chestnut may carry self. A solid rabbit may produce broken kits when paired with a broken mate. This is why genotype choices are useful. They let breeders estimate hidden recessive traits before planning a pairing.

Using Probabilities

This calculator uses simple Mendelian crossing. It builds possible gametes from each parent. Then it combines matching loci, one gene group at a time. The final percentage is the multiplied chance across all selected loci. The result is an estimate, not a promise. Real litters are small. Random chance can make one litter look different from the long term average.

Reading the Results

Focus on the largest percentages first. Those colors are the most likely outcomes. Smaller percentages still matter. A rare result can appear in one kit. Carrier notes help you see hidden genes. They can guide future pairings and prevent surprises. The expected kit count uses your litter size estimate. It shows how often each result may appear in an average litter.

Breeding Notes

Use this tool for planning, records, and education. Confirm uncertain genotypes with pedigree data when possible. Avoid selecting only for color. Holland Lop quality also includes health, temperament, structure, and responsible placement. Color plans should support a wider breeding goal. Keep notes for each litter. Over time, records improve genotype confidence and make predictions more reliable.

Important Limits

Rabbit genetics can include extra modifiers. Rufus, wide band, smut, silvering, and incomplete records can change appearance. Lighting and age can also affect identification. Treat every percentage as a planning aid. For complex projects, compare the prediction with breeder records, pedigrees, and photos from related animals before making decisions. This always keeps expectations clear and practical.

FAQs

Is this calculator exact?

No. It estimates probability from selected genotypes. Real litters are small, so chance can vary. Pedigree accuracy also affects results.

Can a visible color hide other genes?

Yes. Many rabbits carry recessive genes without showing them. A black rabbit may carry chocolate, dilute, non-extension, or white masking genes.

What does broken mean?

Broken describes a white patterned rabbit with colored areas. It is usually linked to the En gene. Two broken rabbits may create charlie pattern risk.

What is a Vienna carrier?

A Vienna carrier has one Vienna allele. It may show marks or look normal. Two carriers can produce blue eyed white kits.

Why does ruby eyed white hide color?

The c/c genotype masks the visible coat color. The rabbit still has other genes, but the white phenotype covers them.

What does expected kits mean?

It multiplies the outcome chance by your litter size estimate. It is an average guide, not a guarantee for one litter.

Can I use unknown genotypes?

Use the closest supported choice. If a genotype is unknown, select the visible match and update it when pedigree or litter data confirms carriers.

Should color be the only breeding goal?

No. Health, temperament, structure, records, and responsible homes matter more. Color planning should support ethical breeding choices.