Simulate Grandparents Coordinates
Estimate other grandparents from grandchild and one known grandparent (~25% each).
This tool estimates the average G25 coordinates of the unknown grandparents when you know the grandchild and one grandparent's coordinates.
Formula: OtherGrandparents = (Grandchild - Percent × KnownGrandparent) / (1 - Percent)
Default contribution is 25% (typical for one grandparent).
Reconstructing a relative who never tested?
This tool gives a quick estimate of the unknown grandparents' coordinates. The Second Parent Report does the full reconstruction of an untested parent from the child and the known parent, with closest populations and an AI interpretation in a PDF.