Blood Type Calculator

Health

Determine possible child blood types and Rh factor from parent blood types based on ABO and Rh genetics.

Formula

ABO blood type from allele combinations; Rh from dominant/recessive inheritance
  • A and B are dominant; O is recessive. AB has codominant expression.
  • Rh+ is dominant; both Rh+ parents can have Rh− child if both carry the recessive allele.
  • This is a simplified model — actual genetics involves more allele variations.

A+ × B+ parents

Inputs
  • Parent 1 Blood Type: A+
  • Parent 2 Blood Type: B+

Possible ABO: A, B, AB, O. With Rh: A+, A−, B+, B−, AB+, AB−, O+, O−.

Frequently asked questions

Can O parents have AB child?
No — both O parents can only produce O children (O×O = O only).
Can Rh- parents have Rh+ child?
No — two Rh− parents always produce Rh− children (recessive×recessive = recessive only).
Is this scientifically accurate?
Simplified. Actual blood typing involves multiple alleles and the Bombay phenotype. For paternity testing, consult a genetics lab.
What is the universal donor?
O− (O negative) is the universal donor for red blood cells. AB+ is the universal plasma donor.