Compare two CSV files online, cell by cell

Drop two CSV exports (spreadsheet, business software, database): difftool.fr shows them as a table and highlights, cell by cell, what changed. Added or removed rows, new or renamed columns, changed values: everything is spotted, without the files ever leaving your computer.

How it works

Open or drag the first file on the left and the second on the right (or paste their content).
The separator is detected automatically: comma, semicolon, tab or vertical bar.
The table of differences appears: one row per line of the file, one column per column.

Quoted values that contain separators or line breaks are read correctly.

Reading the table

An added row has a blue background and a +; a removed row has a red background and a −.
In a changed row (marked ~), each changed cell shows the old value struck through above the new one, underlined. Unchanged cells stay neutral.
The first two columns give the row’s line number in each file.
The summary counts rows added, removed and changed, cells changed, columns added or removed, and the share of identical cells.

Moved columns and rows

When the first row contains column names (“First row = headers”, ticked by default), columns are matched by name: a column inserted in the middle does not cause false differences in all the following ones. A renamed column shows both its old and new names.

Rows are matched like lines in a diff: an inserted row shifts the rest without marking everything as changed. In a reworked section, rows that look alike (at least half of their cells, or half of their words, in common) are put side by side.

Frequently asked questions

How do I compare two Excel files?

Save each workbook as CSV in Excel (File, Save As, CSV), then drop both files here. You can also copy the cells in Excel and paste them into the boxes: they arrive tab-separated, which difftool.fr recognises.

Are my files sent anywhere?

No. The files are read and compared in your browser. No data, even a customer or order file, is sent or kept.

Does row order matter?

Yes: as in a diff, rows are compared in the order of the files. If one export is sorted differently, sort both the same way (for example by the ID column) before comparing.

What if the columns are in a different order?

With “First row = headers” ticked, columns are matched by name. A moved column, however, shows up as removed in one place and added in another.

Do case and spaces matter?

By default, yes. Tick “Ignore case” or “leading and trailing spaces”: these options then apply to every cell. “Ignore blank lines” skips rows whose cells are all empty.

Can I export the differences?

Yes: “Print / PDF” prints the table of differences, and “Download .diff” saves the line-by-line differences in unified format.