Blood Type Calculator
Calculate possible child blood type
Parent 1
Blood group (ABO)
Rh factor
Parent 2
Blood group (ABO)
Rh factor
Blood Type Calculator - Work Out Your Child's Blood Type
Our blood type calculator works out the probability of each blood type for a child based on the parents' blood types. It uses ABO system and Rh factor inheritance according to Mendelian genetics.
How does blood type inheritance work?
Blood type is determined by genes inherited from both parents. The ABO system has three alleles: A, B and O. A and B are dominant over O. The Rh factor (+ or -) is inherited independently - the Rh+ allele is dominant over Rh-.
Frequently asked questions
Can two type O parents have a child with a different blood type?
No. Both parents with type O have genotype OO, so the child can only inherit O - they will have type O.
Is this calculator 100% accurate?
The calculator shows probabilities based on standard genetics. In very rare cases, genetic mutations can give unexpected results.
What is the Rh factor?
The Rh factor is a protein on the surface of red blood cells. Rh+ (present) is dominant over Rh- (absent). About 85% of the population is Rh+.