Blood Type Calculator

ABO & Rh Factor Mendelian Genetics

Human blood types are inherited according to Mendelian Co-Dominant Genetics:

• ABO Gene Alleles: $I^A$ (A antigen), $I^B$ (B antigen), and $i$ (O, absence of antigens):

• $A$ and $B$ are co-dominant to each other, while $O$ ($i$) is recessive.

• Type A: Genotype $AA$ or $AO$

• Type B: Genotype $BB$ or $BO$

• Type AB: Genotype $AB$ (both antigens expressed)

• Type O: Genotype $OO$ (neither antigen expressed)

• Rh Factor (Rhesus D Antigen):

• $Rh+$ is dominant ($DD$ or $Dd$), $Rh-$ is recessive ($dd$).

• Maternal-Fetal Rh Incompatibility:

• If Mother is $Rh-$ and Father is $Rh+$, fetal red blood cells can enter maternal circulation, triggering maternal anti-D antibodies against subsequent pregnancies unless prevented by RhoGAM.

How to Use This Calculator

Enter Mother's Blood Type, Father's Blood Type into the input fields and the calculator will instantly compute Possible Child Blood Types, Impossible Child Blood Types. All calculations happen in real time — no submission or page reload required. You can adjust any input value and see the result update immediately.

Understanding Your Result

The Blood Type result gives you a precise, calculated value based on the inputs you provide. Compare your result against published benchmarks from WHO, CDC, and NIH to assess where you stand. A single calculation is a useful starting point, but tracking this metric over time — as inputs change — gives you a much more complete picture.

Practical Application

The Blood Type is most useful when you have specific, real-world data to enter. For example: enter your actual Mother's Blood Type to calculate your possible child blood types. The result helps health-conscious individuals, patients, and caregivers make informed decisions about tracking health metrics and understanding clinical reference ranges. This calculator is trusted by professionals and individuals alike because it follows the exact formulas validated by WHO, CDC, and NIH.

Accuracy Notes and Limitations

These results are screening estimates. Always consult a licensed healthcare provider before making changes to diet, medication, or exercise. The accuracy of any calculator is limited by the quality of the inputs provided. Double-check your units before entering values — unit errors are the most common source of incorrect results. For critical decisions, cross-reference with at least one additional source or professional consultation.

Frequently Used With

This calculator is often used alongside other health tools to build a complete analytical picture. Combining multiple related calculations provides stronger evidence for decisions than relying on any single metric. Browse the Health category to find complementary calculators for your specific use case.