---
title: "Ancestry percentage calculator"
description: "See what your ancestors' origins add up to as ancestry percentages, and how much your DNA could realistically vary."
canonical: "https://kleiobase.com/tools/ancestry-calculator"
---

# Ancestry percentage calculator

See what your ancestors' origins add up to as ancestry percentages, and how much your DNA could realistically vary.

This tool runs in your browser. Files and dates you enter are never uploaded.

The ancestry percentage calculator works out what your family tree adds up to. Fill in where your ancestors came from, as far back as you know, and it shows your ancestry as percentages, along with the range your DNA could show for each one.

## How to use it

1. Start with your grandparents. Type where each one came from, in your own words.
2. The tree starts at your great-grandparents. If you know more, press **+** on an ancestor to add their parents, up to 6 generations back. Drag to move around the tree and use the zoom buttons to see more of it at once.
3. If an ancestor had mixed origins, choose **Split into percentages** and enter each origin with its share. The shares must add up to 100%.
4. Hover over a slice of the chart to see which ancestors it came from.
5. Save the result as an image, or share it with a link.

A parent or grandparent you leave blank is worked out from the ancestors you entered behind them. The part of your tree that is still unknown shows as a gray slice.

## Why your DNA test can disagree with your family tree

Your family tree says each grandparent is 25% of you. Your DNA does not work that neatly. Each parent passes on a random half of their DNA, cut and mixed in large pieces, so you might carry 21% from one grandparent and 29% from another. Each generation further back, the spread gets wider.

So next to each origin the calculator shows a likely range. It covers the middle 90% of thousands of simulated inheritances, and if your DNA test falls inside it, your paper trail and your DNA agree.

A DNA test can also differ for other reasons. It compares you with groups of people living today, and neighbouring populations often look alike in DNA. So its categories rarely line up with the places in your records. Beyond about 7 generations many of your ancestors left you no DNA at all, and a small origin in your tree can vanish from your results. The paper trail itself can be wrong too. A record may name the wrong birthplace, or a family story may have shifted over the years, so a large mismatch is worth checking against the original records.

## Percentages by generation

| Generations back | Who | Share of your tree each |
| --- | --- | --- |
| 1 | Parents | 50% |
| 2 | Grandparents | 25% |
| 3 | Great-grandparents | 12.5% |
| 4 | 2x great-grandparents | 6.25% |
| 5 | 3x great-grandparents | 3.13% |
| 6 | 4x great-grandparents | 1.56% |

## Frequently asked questions

### Is this the same as a DNA ethnicity estimate?

No. This works out what your family tree says on paper. A DNA test compares your actual DNA with reference groups. The two often disagree, and the range shown for each origin is how far they can drift apart before anything is wrong.

### Why does each grandparent count as 25%?

You get half your DNA from each parent and they got half from each of theirs, so on average each grandparent gives you a quarter. The real share varies, usually somewhere between about 19% and 31%, because DNA is passed down in random chunks.

### Can I give one ancestor more than one origin?

Yes. Choose "Split into percentages" on any ancestor and enter each origin with its share, for example 62%, 30% and 8%. The shares must add up to 100%. You can then leave everyone behind that person blank.

### Why does the tree stop at 6 generations?

At 6 generations back each ancestor is about 1.6% of your family tree, and many ancestors that far back left you no DNA at all. Going further back would show precise-looking numbers that your DNA cannot reflect.

### Is what I type stored anywhere?

No. Everything runs in your browser. Your tree is kept on your own device so it is still there if you reload, and nothing you type is sent to KleioBase or anyone else. A share link carries your result inside the link itself.

Canonical: https://kleiobase.com/tools/ancestry-calculator