Blood Type Calculator
Child's blood type from parentsRuns locally · nothing uploaded
Rh factor: The child could be: Rh positive, Rh negative
Type A can be AA or AO, and type B can be BB or BO. Without the genotype only possible/impossible can be shown; if you know it (e.g. a type A person with a type O parent must be AO), pick it to see probabilities.
Estimates based on general formulas, for information only. Not a substitute for professional medical advice, diagnosis or treatment.
Based on standard Mendelian inheritance. Rare types (cis-AB, Bombay), transfusions and bone-marrow transplants can be exceptions, so blood type cannot establish parentage; use a DNA test for that.
How it works
Formula
A = AA or AO; B = BB or BO; AB = AB; O = OOA and B are dominant over O and codominant with each other.
Rh positive = DD or Dd; Rh negative = ddWorked example
Given: Father type A (AO), mother type B (BO)
- The father passes A or O, the mother B or O: AB, AO, BO, OO are equally likely.
Result: A, B, AB and O are each 25% likely.
Limitations
- Rare types such as cis-AB and Bombay are exceptions.
- Blood type cannot establish parentage.
Sources
- Daniels G. Human Blood Groups. 3rd ed. Wiley-Blackwell; 2013.
How to use
- 1Choose each parent's ABO and Rh type.
- 2Add genotypes if you know them to see probabilities.
- 3Read the child's possible blood types.
FAQ
What blood type can a child of A and B parents have?
Any of A, B, AB or O. If the parents are AO and BO, each is 25% likely.
Can two O parents have an A child?
Not under normal inheritance; two O parents only have O children.