3rd great-grandchild
A 3rd great-grandchild is a relative to whom you are a 3rd great-grandparent. The same page covers both terms.
The route
Red line: from you (the shared ancestor) and 5 steps down. Gold: the shared ancestor.
How to count it
This is a direct-line relationship, so there is no cousin degree. The other person is 5 generations below you in your own line of descent. The number of steps is the whole rule.
Cousin counting is the standard genealogical convention. Different families and legal systems sometimes use looser words, so check the naming conventions guide if a relative uses a different term.
Facts at a glance
| Term | 3rd great-grandchild |
|---|---|
| Reciprocal | 3rd great-grandparent |
| By gender | Man: 3rd great-grandson. Woman: 3rd great-granddaughter. |
| Steps up (a, b) | 0, 5 |
| Civil-law degree | 5 |
| Canon-law degree | 5 |
| Average DNA shared (full) | 3.13% |
Full and half
In a direct line there is no full or half version: the link is the same however many partners a parent has had. Each generation halves the expected DNA, so the figure above applies.
The DNA numbers are theoretical averages. Real amounts vary a lot from one pair to the next, especially for distant cousins, so read the DNA guide before comparing against a test.
Check your own relationship in the calculator, or see where this term sits on the chart.
Nearby terms
- Before: great-great-grandchild
- After: 4th great-grandchild
- All terms