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Health Calculators

Blood Type Calculator

Estimate child ABO and Rh probabilities from two parents’ blood types, with a Punnett-style table and phenotype reference.

Select mother and father phenotypes (A/B/AB/O with Rh+ or Rh−). The tool uses the same population assumptions as blood type calculator: A and B parents are modeled as 75% / 25% AO vs AA or BO vs BB, AB as 50/50 A/B gametes, and O as OO.

Rh probabilities follow Rh+ × Rh+ = 93.75% / 6.25%, Rh+ × Rh− = 75% / 25%, and Rh− × Rh− = 100% Rh−.

Chance for type A
50%
Chance for type B
12.5%
Chance for type AB
37.5%
Chance for type O
0%
Chance for Rh+
75%
Chance for Rh-
25%
♂️\♀️AOAA
AAAA0AAAA
BABB0ABAB

Punnet square for possible blood types

PhenotypeGenotype
AAO or AA
BBO or BB
ABAB
OO