Blood Type Calculator
Pick both parents’ ABO and Rh types — the calculator lists every blood type the child could genetically have.
How to use
- Select parent A’s blood type and Rh factor.
- Select parent B’s blood type and Rh factor.
- All possible child ABO types and Rh factors appear instantly.
Frequently asked questions
Which blood types can my child inherit?
It depends on both parents’ ABO genotypes. A and B are dominant, O is recessive, and AB is co-dominant — so two AB parents can only have A, B or AB children, while two O parents can only have O. The calculator enumerates every possibility from the standard Punnett logic.
Why can two type-A parents have an O child?
A parent with type A blood may carry the silent O allele (genotype AO). If both pass the O allele, the child is type O — the classic surprise in family genetics.
How does the Rh factor work?
Rh+ is dominant. An Rh+ parent may be homozygous (DD) or heterozygous (Dd); the calculator conservatively treats Rh+ parents as possibly heterozygous, so an Rh+ × Rh− pairing lists both Rh+ and Rh− children. Two Rh− parents can only have Rh− children.
Why does Rh matter in pregnancy?
If an Rh− mother carries an Rh+ baby, her immune system can develop antibodies against the baby’s blood (Rh sensitization), which affects later pregnancies. Preventive treatment exists — this is why blood types are checked early in prenatal care.
Can this tool tell me my actual blood type?
No — it only lists what is genetically possible from parents. Real blood type comes from a lab test; rare exceptions (like cis-AB or Bombay phenotype) exist that simple ABO inheritance does not cover.