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What Are the Odds?NEW Read the FAQview in v2

Target name: Target

My research question is: Enter the question you are trying to answer here

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This is an example tree. Create a new tree by clicking here

You are viewing this tree in read-only mode. If you would like to make edits, please click Save and make a copy in your DNA Painter account first.

Hover over a person for options. Scroll to the right to see children.


You are currently in read only mode. If you make edits to this tree, they will not be saved. If you'd like to save it to your DNA Painter account, please sign in or register (free). You'll then see the option to save a copy of this tree.

Experimental: you can save an image of this tree. The results may vary according to your browser. For the best results, try to maximize the size of the window before clicking this button. This feature works best in the Chrome, Firefox and Safari browsers.

You can also download the data for this tree locally and load it back into the tool later (or send it to someone else so they can load it in).

To do this, click the button below.


Click to add notes


After you've added matches and hypotheses to a tree, hypotheses will appear here.

Score calculation

This table shows the shared cM and probability data for each match.

For each hypothesis, the following is displayed:

  • The genealogical relationship with each match based on the tree position of the hypothesis
    (for example 3rd cousin)
  • The probability that the amount of cM shared corresponds to this relationship

These individual probabilities are then used to calculate the combined odds ratio used for the score

The odds ratios are made by comparing all hypotheses that are considered possible and then determining the relative likelhood of each. For more information please see the FAQ.

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About this tool

This tool has been built to help solve DNA puzzles (including unknown parentage cases) by undertaking the calculations described by Leah Larkin in her series Science the heck out of your DNA...

© DNA Painter 2018-2020


Due to the lack of statistical data available, this tool has limited applications to the following scenarios:

  • Double-cousin relationships
  • 3/4 sibling relationships
  • Matches with endogamous ancestry


The underlying calculations that convert the compounded probabilities into the odds ratio used for the score were developed by Dr. Andrew Millard.

Valuable advice on the user interface and functionality was provided by Mike Mulligan. Many thanks also to the early beta testers from the GG&T group on Facebook.

The static tree layout is derived from an example by Peiwen Lu.