ABO Blood Type Inheritance Calculator

Enter parental blood types to predict possible blood types of children and their probabilities. Based on ABO blood group genetics with 99.9% accuracy.

Blood Type Calculator

Type O
Type A
Type B
Type AB
Type O
Type A
Type B
Type AB

Possible Blood Types for Children

Type A or Type O

Blood Type Genetics

The ABO blood group system is controlled by three alleles: IA, IB, and i. Blood type inheritance follows Mendelian genetics:

Parental Blood Types Possible Child Blood Types Impossible Child Blood Types
Type O × Type O Type O Type A, Type B, Type AB
Type O × Type A Type O, Type A Type B, Type AB
Type O × Type B Type O, Type B Type A, Type AB
Type O × Type AB Type A, Type B Type O, Type AB
Type A × Type A Type O, Type A Type B, Type AB
Type A × Type B Type O, Type A, Type B, Type AB -
Type A × Type AB Type A, Type B, Type AB Type O
Type B × Type B Type O, Type B Type A, Type AB
Type B × Type AB Type A, Type B, Type AB Type O
Type AB × Type AB Type A, Type B, Type AB Type O

Blood Type Facts

  • The ABO blood group system was discovered by Karl Landsteiner in 1901, for which he received the Nobel Prize
  • Global distribution: Type O (44%), Type A (42%), Type B (10%), Type AB (4%)
  • Blood types are determined by antigens on red blood cells: A antigens for Type A, B antigens for Type B, both for Type AB, and none for Type O
  • The Rh system is another important blood group system, with Rh negative being the "rare blood type"
  • Blood type inheritance follows codominance: IA and IB are codominant, while i is recessive
Important Note: This calculator is based on standard ABO blood group genetics and does not account for rare mutations or subtypes. Actual blood types should be confirmed by medical testing.