Can you please tell me what I have done wrong in my calculation? I added all the Centimorgans from my Gedmatch chart and it gave a total of 3587 which is 52.7%

It should have been 50% only. The implication of greater than 50% is that some time in the past her mother and I share a common relative.


2 Answers 2


The different companies use different cM for the 22 chromosome pairs. GEDmatch's total is 3587 cM excluding X and Y. See http://isogg.org/wiki/CentiMorgan

Note this is half of what the 44 chromosomes total. The way matches are done, companies cannot distinguish between the paternal and maternal chromosome of each pair, so the total cM for matching purposes is 50%.


I have found out that different groups use different cM dividers. Some divide the cMs by 68 and some by 74. Using 3587/68 gives a 52.7% match and using 74 gives a 48.7% match. It seems logical that for parent and child 50% would be correct so dividing the total cMs (3587) by 71 (or 71.7) would be more logical.

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