Understanding your heritage often begins with a single question: How much of an ethnicity do I carry from a specific ancestor? Use our Ethnicity Percentage Calculator to estimate your genetic inheritance based on genealogical generations.
Ethnicity Percentage Calculator
Ethnicity Percentage Calculator Formula
Formula Source: International Society of Genetic Genealogy (ISOGG)
Variables:
- n: The number of ancestors at a specific generation level who are 100% of that ethnicity.
- g: The number of generations back the ancestors are (e.g., Parent = 1, Grandparent = 2).
- 2^g: The total number of ancestors you have at that specific generation level.
Related Calculators
- DNA Segment Correlation Tool
- Cousin Kinship Calculator
- Centimorgan to Percentage Converter
- Genetic Recombination Estimator
What is an Ethnicity Percentage Calculator?
An ethnicity percentage calculator is a tool used to estimate the theoretical amount of DNA or heritage inherited from specific ancestors. Because humans inherit roughly 50% of their DNA from each parent, each generation back halves the expected contribution of a specific ancestor.
This tool uses the genealogical model of inheritance. While real-world DNA testing may show slightly different results due to “random recombination,” this mathematical approach provides the baseline expectation for genealogical research and family tree planning.
How to Calculate Ethnicity Percentage (Example)
If you discover that one of your Great-Great-Grandparents was 100% Italian, here is how you calculate your share:
- Identify the generation level: A Great-Great-Grandparent is 4 generations back.
- Calculate total ancestors at that level: 2 to the power of 4 ($2 \times 2 \times 2 \times 2$) = 16 ancestors.
- Divide the number of target ancestors (1) by the total (16).
- Multiply by 100 to get the percentage: $(1 / 16) \times 100 = 6.25\%$.
Frequently Asked Questions (FAQ)
Is this calculator 100% accurate for DNA tests? No, DNA inheritance is random. You might inherit 23% or 27% from a grandparent rather than exactly 25% due to recombination.
Why does my DNA test show different percentages than my tree? This is often due to “pedigree collapse” (ancestors appearing more than once) or simply because some DNA segments were not passed down over generations.
What generation is a Great-Grandparent? A great-grandparent is considered the 3rd generation back (Parent 1, Grandparent 2, Great-Grandparent 3).
Can I have 0% of an ethnicity from a 5th-generation ancestor? Yes. Statistically, it is possible to inherit zero DNA segments from a specific 5th or 6th-generation ancestor, even if they are in your tree.