Autosomal Match Quality

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The quality of an Autosomal DNA match is measured by the total percentage of shared DNA as well as the longest segment in common (measured in centimorgans, or cM). Autosomal matches are first compared to specific ranges that are defined for close relatives:

Relationship Total Overlap Longest Segment
Parent / Child 3539-3748 280-290
Sibling 2643-2802 50-141
Nephew / Niece / Uncle / Aunt 1526-2082 95-163
Half-sibling 1320-2100
Double First Cousin 1480-1520
Grandparent / Grandchild 1087-2297
Great- Grandparent / Grandchild 572-1231
Great- Uncle / Aunt / Niece / Nephew 550-860 60-135
Half- Nephew / Niece / Aunt / Uncle 684-1122 54-112
1st Cousin 548-1034 50-182
Half 1st Cousin 320-330 30-35
1st Cousin Once Removed 220-638 34-106
Half 1st Cousin Once Removed 195-205 23-33
1st Cousin Twice Removed 107-426 21-64
2nd Cousin 101-378 31-61
2nd Cousin Once Removed 19-197 19-81
2nd Cousin Twice Removed 12-73
3rd Cousin 43-150
3rd Cousin Once Removed 11-99
4th Cousin 5-50 0-24
5th Cousin 0-33 0-10


If none of the above criteria are met, the match is grouped into four tiers:

  • Immediate Relative - Likely to be a parent, child, sibling or half-sibling
  • Close Relative - Likely to be first or second cousin
  • Distant Relative - Likely to be a 3rd, 4th or 5th cousin
  • Speculative Relative - Likely to be a 6th cousin or further
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