Blood Type Calculator
Blood Type Calculator Quickly estimate a baby's possible ABO and Rh blood types from parents using genetics rules, Punnett squares, and probability calculations.
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Helping Notes
Outputs show probabilities for child ABO (A, B, AB, O) and Rh (+/−) from Punnett-style crosses using standard genotype assumptions.
Because parent phenotype can map to multiple genotypes (e.g., A = AA or AO), this tool assumes 50/50 when ambiguous.
Educational aid only—does not replace clinical testing. Field set mirrors Omni’s calculator: just the two parent blood-type selects. :contentReference[oaicite:2]{index=2}
Results
Chance for A
Chance for B
Chance for AB
Chance for O
Chance for Rh+
Chance for Rh−
What Is a Blood Type Calculator?
A Blood Type Calculator predicts a child’s possible ABO and Rh blood groups using classical inheritance. It combines each parent’s likely genotypes and computes probabilities for outcomes like A, B, AB, or O, and Rh positive or negative. Behind the scenes, it multiplies the chances of parental alleles being passed down, then sums results that map to the same phenotype. This helps with education, curiosity, and planning discussions with healthcare professionals.
About the Blood Type Calculator
The tool models two systems: ABO (alleles IA, IB, and i) and Rh (alleles D and d). In ABO, IA and IB are codominant; i is recessive. In Rh, D is dominant over d. Phenotypes derive from genotypes:
- A ⇐ {IAIA, IAi}
- B ⇐ {IBIB, IBi}
- AB ⇐ {IAIB}
- O ⇐ {ii}
- Rh+ ⇐ {DD, Dd} Rh− ⇐ {dd}
Core probability model: P(child ABO = X) = Σg∈GX P(g), where P(g) = P(g₁ from P1) × P(g₂ from P2)
Rh positivity: P(Rh+) = 1 − P(d from P1) × P(d from P2)
How to Use This Blood Type Calculator
- Select each parent’s known blood group (A, B, AB, O) and Rh status (+/−). If uncertain, choose options that include both common genotypes (e.g., A could be IAIA or IAi).
- Submit to compute probabilities for each child outcome (e.g., A+, A−, B+, B−, AB+, AB−, O+, O−).
- Review results, which aggregate genotype-level probabilities into phenotype-level percentages for easy interpretation.
Examples
- Parent A (A, likely IAi) × Parent B (B, likely IBi): child ABO outcomes A, B, AB, O ≈ 25% each.
- Parent O (ii) × Parent AB (IAIB): child outcomes A or B ≈ 50/50; AB and O are 0%.
- Parent A (IAIA) × Parent O (ii): all children type A (100%).
- Rh example: Dd × dd → Rh+ ≈ 50%, Rh− ≈ 50%.
Formula Snippets Ready for Rendering
FAQs
Can two O parents have an AB child?
No. Two O (ii × ii) can only produce O.
Can two AB parents have an O child?
No. AB × AB cannot produce ii.
Can two A parents have an O child?
Yes, if both are IAi; probability ≈ 25% for ii.
Can A and B parents have an AB child?
Yes, especially when both carry dominant alleles.
Can an O parent and an AB parent have an O child?
No. Outcomes are A or B only.
Is the calculator a medical test?
No. It’s an educational estimator; confirm types with laboratory testing.
How accurate are the probabilities?
Genetically accurate under model assumptions; real-world allele frequencies may vary.
Can blood type change over time?
Generally no, except rare biological phenomena (e.g., chimerism, transplants).
What if I don’t know genotypes?
The tool considers all consistent genotypes and averages probabilities accordingly.
Can a negative mother and positive father have a negative baby?
Yes, if the father carries d (Dd × dd → 50% Rh−).
Does ethnicity affect results?
Base rules don’t change, but allele frequencies differ by population.
Why don’t outputs include rare subtypes?
To keep results clear; specialized subgroups require advanced typing.
Is AB the universal recipient?
For red cells, yes; O is the universal donor (crossmatch rules still apply).
Can this predict exact genotype?
No. It returns phenotype probabilities; genotypes may remain ambiguous.
Should I use this for medical decisions?
Consult clinicians for guidance; use this tool for learning and planning conversations.