What is the Blood Type Inheritance Calculator?
Predict possible child blood types from parent ABO and Rh factors. Set parent types A, B, AB, or O with optional genotype detail, then see combined outcomes (e.g. A+, O−) with probabilities, ABO and Rh Punnett squares, and separate locus breakdowns. Free, private, and instant in your browser.
How to use the Blood Type Inheritance Calculator
- Select Parent 1 and Parent 2 ABO blood types.
- For type A, B, or Rh+, choose genotype if known or leave as unknown.
- Review combined child blood type probabilities.
- Inspect ABO and Rh Punnett squares separately.
- Copy the summary for genetics homework or family planning education.
Common use cases
- Learning ABO inheritance for a biology class
- Checking whether two O parents can have a non-O child (they cannot)
- Explaining Rh factor inheritance to expectant parents
Frequently asked questions
- How is blood type inherited?
- ABO blood type is controlled by the A, B, and O alleles. A and B are codominant; O is recessive. Rh+ is dominant over Rh−. The two loci are treated independently in this calculator.
- What does unknown genotype mean for type A or B?
- If a type A parent could be either AA or AO, unknown assumes a 50% chance of each genotype before calculating offspring probabilities.
- Can two type A parents have a type O child?
- Yes, if both parents are heterozygous (AO). Each can pass an O allele, giving a 25% chance of an OO child with phenotype O.
- Can an Rh− parent have an Rh+ child?
- Yes, if the Rh− parent is dd and the Rh+ parent is Dd, there is a 50% chance the child inherits D and is Rh+.
- Is my data uploaded?
- No. All calculations run locally in your browser.
