About

Understanding one's heritage is often more complex than a single label. As families blend across borders, the question of identity moves from qualitative description to quantitative analysis. This tool provides a mathematical breakdown of ethnic composition by aggregating the backgrounds of ancestors up to the great-great-grandparent level.

Accuracy in genealogy requires handling geometric progressions of fractional inheritance. Each generation represents a halving of genetic contribution: parents (0.5), grandparents (0.25), and so on. This calculator manages these fractions to produce a composite profile, essential for users reconstructing family trees without biological testing. It eliminates the ambiguity of mixed-heritage estimation by applying strict weighted averaging.

Formulas

The total composition C for a specific ethnicity e is the sum of contributions from all ancestors A possessing that ethnicity, weighted by their generational distance g.

C_e = N∑i=1 12^g_i × match(A_i, e)

Where match returns 1 if ancestor A_i belongs to ethnicity e, and 0 otherwise. The sum of all C_e must equal 1 (or 100%).

Reference Data

Generation	Contribution Factor (n)	Formula	Share (%)
Parents	n = 1	12¹	50.0%
Grandparents	n = 2	12²	25.0%
Great-Grandparents	n = 3	12³	12.5%
Gt-Gt-Grandparents	n = 4	12⁴	6.25%
Gt-Gt-Gt-Grandparents	n = 5	12⁵	3.125%

Frequently Asked Questions

The logic supports calculations down to the 5th generation (Great-Great-Great-Grandparents), where the contribution is roughly 3.125%. Beyond this point, records often become unreliable, and the genetic contribution becomes statistically negligible for general heritage overview.

Yes. This system treats every input as an absolute value for that specific branch. If a parent is mixed, you should instead input their parents (your grandparents) to ensure mathematical accuracy in the final summation.

This usually occurs if an ancestor slot is left empty or "Unknown". The tool calculates based on the known inputs. To correct this, assign "Unknown" or "Other" to missing slots to visualize the gap in the genealogy.

No. This is a genealogical calculation based on reported family history. DNA recombination is random; you might inherit 20% from one grandparent and 30% from another, rather than exactly 25% from each. This tool models the "expected" heritage based on lineage, not biological expression.