Blood Type Calculator: Child From Parents
This blood type calculator predicts which blood types a child can have, based on the ABO group and Rh factor of both parents. Each parent passes one ABO gene (A, B or O) and one Rh gene (positive or negative), so a parent with type A can carry a hidden O. The calculator lists every possible genotype, combines them in a Punnett square and shows the chance of each child blood type, from O negative to AB positive. It also lists which blood types are not possible for the child.
Blood Type Calculator
Find the possible blood types of a child, with percentages, from both parents' ABO and Rh types.
How to use the Blood Type Calculator
- Choose the first parent's blood type.
- Choose the second parent's blood type.
- Optionally set known genotypes, such as AO or BB.
- Read each possible child blood type and its chance.
How blood type is inherited
Each parent passes one ABO allele (A, B or O) and one Rh allele (D or d). A and B are dominant over O; D (positive) is dominant over d (negative).
Features
- All 8 ABO and Rh types
- Hidden O and Rh negative genes
- Percent chance for each type
- Types that are not possible
Frequently asked questions
Can two O parents have an A child?
No. Two type O parents can only pass O genes, so all their children are type O.
Can two positive parents have a negative child?
Yes. If both parents carry a hidden Rh-negative gene, each child has a 25% chance of being Rh negative.
What blood types can an A and B parent have?
Any of A, B, AB or O, depending on whether the parents carry a hidden O gene.
Why are the percentages estimates?
A type A or B parent can be AA or AO (or BB or BO). Unless you know the genotype, the calculator weighs both options equally.
Can a blood type test prove parentage?
No. Blood type can only rule out some combinations. A DNA test is needed to confirm parentage.