How to Read a Family Tree Diagram: Boxes, Lines and Symbols

Learn to read any family tree diagram: what the boxes, colours, marriage lines, dashed boxes and dates mean, and how to follow a line of descent.

A family tree diagram packs a lot of information into a few simple shapes. Once you know the conventions, you can read a chart of a hundred people in a minute. This guide explains the elements as they appear in charts produced by PrintFamilyTree; most other programs use similar rules.

The boxes

Every box is one person. It shows the name and, when known, the years of birth and death. A birth year alone is written with an asterisk, for example \ 1948*, following the tradition of printed genealogies. Colours are gentle rather than loud: a light blue tone for men, a light rose tone for women, grey when the sex is not recorded.

Marriage lines

A short horizontal line between two boxes joins a couple. The man stands on the left and the woman on the right, so that a row of two boxes always reads the same way. When a person married more than once, they stand between their partners: the earlier marriage on the left, the later one on the right.

Lines to children

From the middle of a marriage line, a vertical line drops to a horizontal bus above the children, and one riser goes up from each child. Children are ordered from left to right by birth when every one of them has a date, and otherwise in the order of your file. A single child gets a straight line with no bus.

If the other parent is unknown, the line to the children starts from the bottom of the parent's own box instead of from a marriage line.

Dashed boxes

Sometimes a person must appear in two places: a cousin who married into the family, a child listed with both biological and adoptive parents, or an ancestor who appears on both the father's and the mother's side. The main box is drawn once with a solid border. Every other occurrence is a dashed box with grey text, which tells you look for this person elsewhere on the chart.

Hops over crossing lines

In most families no line has to cross another. When the data makes a crossing unavoidable, the vertical line makes a small arc over the horizontal one, like a bridge. The arc tells you that the two lines are not connected.

Reading direction

• In an hourglass or pedigree chart, ancestors are above and descendants below. The father's side is drawn to the left of the central person and the mother's side to the right.
• In a descendant chart, the oldest couple is at the top.
• Siblings of an ancestor stand next to that ancestor, on the side away from their spouse, with their own families below them.

Following a line of descent

To trace how two people are related, find both on the chart and walk upward from each until the lines meet. The generation where they meet contains the common ancestors; count the steps down on each side to work out whether you are looking at first cousins, second cousins or cousins once removed.

A note on dates and places

Charts show only what fits in a box. For full dates, places, occupations and sources, a chart is the wrong medium; that is what a family history book is for. The two work best together: the chart on the wall for orientation, the book on the shelf for the details.