Blood Type Calculator

Work out the possible blood types (ABO + Rh) your child could inherit from two parents, with percentage chances.

Parent 1 blood type

Parent 2 blood type

Inheritance 101
Each parent passes one ABO gene (A, B or O) and one Rh gene (+ or −). The letters A and B are dominant over O; + is dominant over −.

So two O parents always have an O child — but an O parent and an A parent can have either A or O children.

🔬 ABO + Rh together

Full 8-type probability breakdown.

🧮 Simple genetics

Classic dominant/recessive inheritance.

📊 Percent bars

See the odds at a glance.

🛏 Rare combos flagged

Impossible pairs called out clearly.