Two versions of a tree, and you want to know what is different. Last year's export and this year's. Your file and the one a cousin sent back with "a few corrections". A website's export and the desktop program's export of what should be the same tree.

Reading two files by eye is hopeless past a few dozen people. Tools > Compare files does it: file A is the file you have open, file B any other file, read privately and never saved or opened unless you ask.

How the records are paired

When file B is a later export of the same tree, its records keep their IDs, and the tool pairs them by ID and says so. When the IDs differ (another program renumbers everything), people are paired by name, dates, places and relatives, and the pairing is shown so you can check it: who was paired with whom and how surely, and who found nobody on the other side. You can force either way of pairing.

What it reports

Four counts first: records only in file B, records only in file A, records that differ, records that are the same. Then, in tabs by kind (people, families, sources, notes, media, other), one line per record in words: "Death, date: 4 NOV 1970 → 5 NOV 1970", "Grace Doyle leaves as a child", "a source added". Each line links to the record's page.

The code view shows the two files side by side, line for line, with the lines only file A has in blue and only file B has in purple, so a single changed line can be seen in the record itself. A Show as dropdown writes both files as GEDCOM, GEDCOM X (JSON or XML), Gramps XML or Gramps CSV, lined up the same way.

Three endings

  • Save the list as text, listed on the Exports page.
  • Open file B in app, saved next to your other files exactly as it was read.
  • Show in app: every page shows both files at once, with what only file A has in blue, what only file B has in purple and what differs in amber, and every person or family carries a banner saying which. Accept in the file menu then saves file B, on file A's IDs, as a new file, so pins and settings carry over; Discard brings file A back.

The two situations where it earns its keep

Before a merge. Compare shows how big the overlap is and where the joins would be. Three shared people can be added by hand. Three hundred needs the Merge trees tool, and now you know where to check its work.

Checking someone else's edits. A relative returns the file with changes. Compare shows exactly what changed, so the corrections can be accepted and the surprises questioned without reading the whole thing.

What it does not do

It does not merge. It does not say which version is right. It shows the differences and leaves the judgment to you.

Next

Export the tree today, and again in six months, and compare the two. It is a good way to see what actually got done.