You get exactly 50% of DNA from each parent. That is the only “exact” thing about DNA. While you get about 25% from each grandparent, that number is an estimate. DNA is inherited randomly, so you might get a higher percentage from one grandparent than another.
Here is how much DNA you inherit:
| YOU | 100% |
| Parents | 50% |
| Grandparents | 25% |
| Great-grandparents | 12.50% |
| Gr-Gr-Grandparents (2) | 6.25% |
| Gr-Gr-Gr-Grandparents (3) | 3.125% |
| Gr-Gr-Gr-Gr-Grandparents (4) | 1.56% |
| Gr-Gr-Gr-Gr-Gr-Grandparents (5) | .78% |
