Shared cM Tool

Enter the total amount of DNA you share with a match (in centimorgans) to see the possible genealogical relationships and their probabilities, based on the Shared cM Project. Then optionally refine the result using ages and the number of shared segments — the more you tell it, the narrower the answer.

Refine your prediction (optional)

Two extra clues dramatically narrow which relationship is likely — inspired by MyHeritage's cM Explainer (ages) and SegcM by DNA‑Sci (segments).

Relationship probabilities

By total cM, based on statistics from The DNA Geek. Most likely first.

  • Enter a cM amount above to see probabilities.

Possible relationships

Relationships whose Shared cM Project range (99th percentile) includes this amount. Add ages/segments above to refine.

  • Nothing yet.
Shared cM Project © Blaine T. Bettinger (CC BY 4.0) · interactive tool by DNA Painter · probabilities via The DNA Geek.

Other relationship tools

Cross-check your result — each tool uses the data a little differently.

About this tool & credits

This is a reproduction of the Shared cM Project 3.0 tool v4, used by permission from Jonny Perl. The original interactive tool is at DNA Painter.

The Shared cM Project data is © Blaine T. Bettinger (The Genetic Genealogist), August 2017, released under a Creative Commons Attribution 4.0 License. The interactive version (v4, with probabilities) was created by Jonny Perl at DNA Painter; relationship probabilities are derived from The DNA Geek.

The optional Refine feature is inspired by MyHeritage's cM Explainer (age-based prediction) and SegcM by DNA‑Sci (dna-sci.com) (segment-count prediction). Our age and segment refinements are approximate heuristics (about 29 years per generation); for rigorous segment-based probabilities, use SegcM.

Predicted relationships are probabilities, not certainties — especially for distant matches, where many relationships share similar amounts of DNA.