Split a large CSV into smaller files

How it works and when to use it

The tool reads your file in the browser with a standard CSV parser, so a quoted cell that contains a line break is treated as part of one row and is never cut in half. It then divides the data rows into groups of the size you choose and writes each group as its own CSV, with the original header row on top. The header does not count toward the row limit.

Splitting helps when a file is too big for the program that has to open it. Excel stops at 1,048,576 rows, many web importers cap uploads at a few thousand or a few hundred thousand rows, and a very large file can freeze a text editor. Pick a row limit under the one that matters, then import the parts one at a time.

Parts are offered as separate download links, named like data-part-01-of-04.csv. Your browser may ask for permission before saving several files in a row. The last part contains whatever rows are left. Files are limited to 50 MB, and nothing is uploaded.

FAQ

Is the header repeated in every file?

Yes. Each part begins with the same header row, so every file can be opened and imported on its own.

Can I split by file size instead of rows?

Not directly. Divide the size limit by the average row size to pick a row count, then check one part.

Is my file uploaded?

No. The file is split by JavaScript in your browser tab, and the parts are created on your computer.