Written by Generation Archives. This explains the chart itself. A printable four-generation version is on our site if you want a blank form, and the same layout appears in most genealogy software.

How to read a pedigree chart

Published by Generation Archives on October 25, 2026. Last updated November 5, 2026.

A pedigree chart answers one question: who are this person's ancestors? It does not try to show every cousin. Once you know where the starting person sits, the rest of the page is a repeating pattern of parents.

The starting person is number 1

On a standard chart, the person you are tracing is at the left, or sometimes at the bottom. That person is number 1. Their father is number 2 and their mother is number 3. The father's parents are 4 and 5. The mother's parents are 6 and 7. The numbers double as you go back: a father's father is twice the child's number, and the mother is the next number.

You do not have to use the numbers. They are there so a second page can say "continued from person 8" without drawing the whole chart again. Four generations on one sheet is person 1 through person 15. That is you, two parents, four grandparents, and eight great-grandparents, if every slot is filled.

How to read a box

Each box is one person. A full box has a name, a birth date and place, and a marriage and death if they apply. Many boxes are half empty. An empty line means the compiler did not have that fact. It does not mean the event happened in the place printed on the line above.

Read across one generation before you jump to the edge of the page. Parents sit next to each other. On left-to-right charts, the father is often the upper of the two lines and the mother the lower. Check the labels. Forms differ, and some charts put the mother on top. The words "father" and "mother," or "parent," matter more than the habit.

Dates on older forms are often day, month, year, with the month written out or abbreviated. "12 Mar 1931" is 12 March 1931, not 3 December. A "c." or "abt" before a year means about. A question mark means the compiler was unsure. Keep the question mark when you copy the box into another tree.

What the chart leaves out

A pedigree is a direct line. Brothers and sisters of person 1 do not appear, except sometimes as a note. Brothers and sisters of the parents do not appear at all. A second spouse usually does not fit in the box. Adoption, step-parents, and guardians are awkward on a form that assumes two biological parents. If a chart shows only one pair of parents, do not assume that is the whole story of who raised the child. Ask, or look for a family group sheet, which has more room.

The chart also does not show why anyone believes the dates. A careful compiler cites sources somewhere else. A chart with no notes is a diagram, not proof.

Using one to see what you still need

Print or open a four-generation chart and fill only what you can say without guessing. The empty boxes are the list of people to ask about. When a box has a name and no place, that place is the next question. When you move the same people into software, the picture on screen may add siblings and second spouses that this one-page form never had room for. The chart and the full tree are answering different questions. The chart is the ancestors of one person. The full tree is the family.

Reading a made-up chart, box by box

Practice helps more than rules. Here is a short fictional chart described in words, with invented people, so you can follow the logic.

Person 1 is Dana Whitfield, born 1994, Duluth. The chart shows two lines going back from her.

Person 2 is her father, Peter Whitfield, born about 1962, Duluth. The "about" tells you the compiler is not certain of the year.
Person 3 is her mother, Lorraine Ames, born 1965, Thunder Bay.
Person 4 is Walter Whitfield, born 1931, Peter's father. Person 5 is Ruth Kessler, Peter's mother, with a birth year but no place.
Person 6 is Joseph Ames?, Lorraine's father, with a question mark and no dates. Person 7 is Margit Ames, Lorraine's mother, with no maiden name.
Persons 8 and 9 are Walter's parents, Henrik Whitfield and Anna Brandt. Persons 10 to 15 are empty.

From this you can read several things without being told. Dana's paternal line is better documented than her maternal line. Persons 10 through 15 are the open research questions. The mother's side has two details that look incomplete: Margit's maiden name and Joseph's confirmed name. And there is no way to tell from the chart how many brothers and sisters Dana has, or whether Walter had siblings, because a pedigree does not show them.

The shortcut for finding anyone

If you want to find a specific person's parents, double their number for the father, and double and add one for the mother. Person 5 is Ruth, and her father would be person 10 and her mother person 11. Both are blank. To go up from a number, divide by two and ignore the remainder. Person 9 is Anna, and 9 divided by 2 is 4 with a remainder, so Anna is a parent of person 4, Walter.

Different layouts, same information

Not every chart looks like the four-generation form on a printed page. You may meet any of these:

Left-to-right (horizontal). The starting person is on the left, and ancestors fan out to the right. This is the most common printed form.
Bottom-up (vertical). The starting person is at the bottom, and ancestors branch upward like a tree. Many software charts use this layout.
Fan charts. The starting person is at the center of a circle, and each generation is a ring. They are compact and good for posters, but names get small in outer rings.
Descendant charts. These look similar but run in the opposite direction, from one ancestor down through all their children. A descendant chart is not a pedigree. If you see a chart with one person at the top and many branches below, check which kind you have.

In every layout, check the labels before you assume which side is father and which is mother. The pattern of doubling numbers will help even if the layout is unfamiliar.

Common ways people misread a chart

Assuming every box has the same level of certainty. A box with a full date and a place is probably from a document. A box with only a name might be from a conversation. A pedigree makes them look equal, so ask.

Reading a blank as a gap in a record. A blank means the compiler did not know. It might be easy to find or genuinely lost.

Assuming the chart lists all the children. It only lists the direct line. A person on the chart may have eight siblings who appear nowhere.

Thinking a long chart means a well-researched tree. Length can come from copying other trees. Check whether sources are cited anywhere. How to cite a photo, letter, or interview shows what a simple citation looks like.

Forgetting the chart is a snapshot. Note the date it was compiled. A chart from 1995 may have been corrected since.

Reading about living people on a chart you were not meant to share. If you are handed a chart, ask before you pass it on. What to record about living people explains why.

Making your own chart

When you are ready to build one, the printable pedigree chart gives you a blank four-generation form in US Letter and A4. If you would rather work digitally, a tree app will draw the same relationships for you. In Generation Archives you can try the demo without signing up. Trees are private by default, and you can arrange people however you like, which helps when a pedigree chart cannot show a step-parent or an adoptive family. If you are starting from almost nothing, how to start a family tree has a checklist, and start from your grandparents is useful if that is all you know.

Frequently asked questions

Why are there numbers in the corners?

So each person has a stable place. Person 1 is the subject. Even numbers in this system are often the fathers and odd numbers the mothers, after person 1. A continuation sheet uses the number instead of repeating the name.

Does the father always go on the top line?

On many printed forms, yes. Some software and some European charts swap the sides or the order. Read the heading in the box before you assume.

How is this different from a family group sheet?

A pedigree follows one person's parents, grandparents, and so on. A family group sheet is one couple and their children. Use both. The pedigree shows the line. The group sheet shows the brothers and sisters the pedigree skips.

What does a question mark in a box mean?

The compiler was not sure of that name or date. Copy the question mark when you copy the entry, and try to find out what the uncertainty was about.

Why is my chart missing a generation?

If the chart is four generations and has 15 boxes, the great-grandparents are the last row. A fifth generation starts on a new chart, where one of those great-grandparents becomes person 1. Look for a "continued on chart" line.

How is a pedigree chart different from a family tree?

A pedigree is a particular kind of tree diagram that only shows direct ancestors. What most people call a family tree usually includes siblings, cousins, and spouses, and it may show descendants too. See adoptive and step-parents in a family tree for how families that do not fit the two-parent pattern are handled.

Can I make one from a GEDCOM file?

Most genealogy programs can draw a pedigree chart from the data in a GEDCOM file. If you want to understand what is in the file, read what is GEDCOM.

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