How to use the blood type inheritance probability calculator
Probability a child has blood type O from two heterozygous A or B parents. Enter parent 1 chance to pass o allele, parent 2 chance to pass o allele in the fields above; the child blood type o, child carries at least one non-o allele are computed instantly and plotted on the chart so you can see how the answer changes.
Formula
Variables
- a1 — Parent 1 chance to pass O allele
- a2 — Parent 2 chance to pass O allele
Worked example
With parent 1 chance to pass o allele = 0.5, parent 2 chance to pass o allele = 0.5, the calculator gives child blood type o ≈ 25 %; child carries at least one non-o allele ≈ 75 %.
Frequently asked questions
What is the formula for the blood type inheritance probability calculation?
Child blood type O (%) = 100 × a1 × a2. Child carries at least one non-O allele (%) = 100-[Child blood type O]. Here a1 is parent 1 chance to pass o allele, a2 is parent 2 chance to pass o allele.
What inputs do I need for the blood type inheritance probability calculator?
You need parent 1 chance to pass o allele, parent 2 chance to pass o allele. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use this calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.