GenerateRandomSearch

Family Tree Generator

A generated family is easy. A consistent one is the point, and it is where hand-built ones fall over: a grandchild born before their grandmother, a cousin married to their own great-aunt, a line that loops back on itself because somebody was pasted in twice. All of those are arithmetic, and arithmetic can be checked. Every family here is read back afterwards — the tree walked upwards from each person, the dates compared, the ancestors of each couple set against each other — and the checks are listed under the result.

What this generator does

Starts with a founding couple and works forward a generation at a time. Each birth falls in a window worked out from both parents — old enough to be a parent, and still alive — so a short-lived parent narrows the window rather than being quietly ignored. Partners marry in from outside the family, which is what keeps the tree from folding back on itself.

How to use this tool

  1. Choose how many generations to run, and the most children a couple may have.
  2. Set the year the founder is born; everything else is dated from it.
  3. Build the family, and read it generation by generation.
  4. Copy the link to keep this family, or the text to paste into your notes.

Understanding the controls

Generations
Three to six after the founding couple. Not every child goes on to have children, which is what stops the family doubling for ever.
Most children per couple
The ceiling, not the number. A couple whose window is too short for that many has fewer.
The founder is born in
Any year. Every other date is worked out from it, so the family can sit in whatever period you are writing.
Repeat word
The word this family was built from. Anyone opening the same link gets the same people and the same dates.

Common use cases

  • A noble house for a campaign, with a succession that stands up to questions
  • Background for a novel spanning several generations
  • A dynasty whose feuds have dates behind them
  • Practice material for teaching how a family tree is read
  • Sharing the same family with everybody at a table from one link

How this generator works

The checks are separate from the building and are driven from the finished tree. Nobody being their own ancestor is proved by walking upwards from every person rather than by reading the generation numbers, because the generation numbers are one of the things being checked. Whether a couple are relations is settled by comparing the two ancestor sets, not by trusting how they were placed.

Randomness and fairness

The family is built from a repeat word drawn from your browser’s secure generator unless you type one of your own, so a link rebuilds the same family. That makes the sequence behind it deterministic and not cryptographic.

For how randomness is produced across the whole site, see how Generate Random works.

Limitations and good to know

  • The people are invented. No real family is being described and none of this is a genealogical record.
  • Everybody born into the family takes the founder’s surname, which is one custom among many.
  • Every couple is one partner married in from outside, so the tree cannot show two branches of the family meeting again later.
  • Nobody has children with more than one partner, and there are no adoptions, remarriages or unrecorded parents.

Privacy and your data

The family is built on your device and nothing about it is transmitted or stored. The repeat word is a short label this page made or you typed, and it is the only thing that appears in the address; it is never measured.

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