No of grandparents in 10 generation

+2 votes
I know this is going to be perceived as a stupid question, I feel stupid for asking: How many grandmothers and grandfathers are there in 10 generations. I thought the count was 1024 but the 'brick wall' function is showing 2048. What am I missing? Thanks.
asked ago in The Tree House by Leigh Anne Dear G2G5 (5.3k points)

4 Answers

+4 votes
Best answer
If your counting grandparents as gen 1, then the answer is 2048.

1  Grandparents = 4

2. GGranparents=8

3. GGGrandparents=16

4. GGGGrandparents=32

5. GGGGGGrandparents=64

6. GGGGGGGrandparents=128

7. GGGGGGGGrandparents=256

8. GGGGGGGGGrandparents=512

9. GGGGGGGGGGRandparents=1024


If your parents are gen 1, then it is 1024. If you are gen 1, then it is 512.
answered ago by Deb Durham G2G6 Pilot (706k points)
selected ago by Steven Harris
+1 vote
A three generation chart has 4.  A four generation has 8.

Five generation has 16.  Six generation has 32.

Seven generation has 64.  Eight generation has 128.

Nine generation has 256. Ten generation has 512.

Total number of grands is 1021.

If instead you have ten generations of grands, and ignore the root person and their parents, then it would be 4096.
answered ago by Joseph Cook G2G1 (1.9k points)
0 votes

It's easy to see that the theoretical number of parents double every generation

"The formula for the number of ancestors in a given generation is:

2n = x

where n is the number of generations back

and x equals the number of individuals in that generation.

But it can be argued that it doesn't quite work that way.

Once upon a time, when many marriages were either out of convenience or to build/protect family wealth, marriages between close family members were not uncommon and in-breeding occured. There is also the possibility of in-breeding from a variety of other activities.

The result is that as the number of generations increases, so does the possibility that some event reduced the the number of distinct ancestors.

Arguments have also been made that by the time you go back 10 generations the DNA has been so diluted, that DNA wise there is almost no relationship (say 1-2 percent) between you and your ancestors.

Others have argued, that given the constant growth from a very small population to a large one, we are somehow all related to each other biologically. 

Still others argue that given the rapid growth of technology, you are more culturally related to your neighbor, than your GGG Grandparents. (Certainly, given enough time, neighbors matter more to our lives than ancestry)

So yes, there is a mathematical formula that will produce a number, it is a theoretical number, arrived at with a lot of assumptions. 


answered ago by Peter Geary G2G6 Mach 3 (31k points)
+2 votes
Generation 0 is yourself. Generation 1 is your parents, and so on until generation 10, your 8th great grandparents.

Because everyone has 2 parents, the formula to see how many ancestors there are in each generation is 2^(number of generations).

So in the 10th generation you have 2^10 (1024) 8th great grandparents. But if you want the total number of ancestors, you have to add the 2^9 (512) 7th great grandparents, and the 2^8 (256) 6th great grandparents... and on and on until you get to 2^1 (2) your parents.

In total, that means you have 2046 ancestors in 10 generations.
answered ago by Jamie Nelson G2G6 Pilot (191k points)

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