What is a fan chart?

5-minute read · Updated September 2026

A fan chart is a family tree drawn as a half circle, or sometimes a full circle. One person sits at the center. Their parents fill the first ring, grandparents the second, great-grandparents the third, and so on outward. It looks like an open hand fan, which is where the name comes from.

How to read it

• The center is the main person, often you, a child or a grandchild.
• Left half = father's side, right half = mother's side. Every ring keeps that rule, so each wedge splits into the father (left) and mother (right) of the person below it.
• Each ring is one generation. Ring 1 holds 2 parents, ring 2 holds 4 grandparents, ring 3 holds 8 great-grandparents. The number doubles every time.
• Colors usually follow a family line. In Fan Chart Studio's default coloring, each of your four grandparents' lines gets its own color, so you can follow a branch back through time at a glance.
• Blank spaces mark ancestors you haven't found yet. Many genealogists hang their chart as a to-do list!

Fan chart vs. pedigree chart

A pedigree chart shows the same people as boxes in columns, with you on the left and ancestors branching to the right. It's great for research because every box has room for full dates and places. A fan chart fits far more people into the same space and is much easier to take in at a glance, which is why it's the favorite for posters and gifts.

Why the numbers work: Ahnentafel

Genealogists number direct ancestors with a system called Ahnentafel (German for “ancestor table”). The main person is 1. For anyone numbered n, the father is 2n and the mother is 2n+1. So your father is 2, your mother 3, your father's parents 4 and 5, your mother's parents 6 and 7. A fan chart is simply this numbering drawn in circles: every ring holds numbers 2^g to 2^g+1−1.

Half fan, ¾ fan or full circle?

• Half fan (180°) is the classic look. It fits a landscape page, with names that are easy to read.
• ¾ fan (270°) gives the outer rings more room while keeping an open, fan-like shape.
• Full circle (360°) fits the most generations for its size, with a dramatic look on a square or portrait poster.

Want to try one by hand?

Print one of our free blank fan chart templates (4 or 5 generations, Letter or A4) and fill in what you know.

What about pedigree collapse?

When cousins married, the same ancestor can appear in two places on your chart. That's called pedigree collapse, and it's normal, especially beyond six generations. Read more about how many ancestors you really have.