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Split a CSV file
Drop a .csv or .xlsx file and cut it two ways: into parts of a fixed number of rows, or into one file per distinct value in a column — one file per region, per month, per account manager. The header row is repeated in every part. Nothing is uploaded.
Open a file
Drop .csv or .xlsx here, or click to choose
Doing this every month? Do it once in TableDI 2, save it as a job, and run it again next month. Download TableDI 2 free
Nothing is uploaded. The file is read by JavaScript in this tab and never leaves your computer — no server sees it, and closing the tab throws it away.
Two ways to split, for two different reasons
Into parts of N rows. Because something downstream has a limit: an import screen that takes 5,000 rows at a time, a bulk-upload form, an API that rejects a payload past a certain size, a colleague whose machine will not open the whole thing. Equal chunks, header repeated, numbered in order.
Into one file per value in a column. Because the rows belong to different people. One file per region to send to each regional manager, one per client so nobody receives another client's rows, one per month for an archive. Files are named after the value, and the parts are listed largest first so you can see the distribution at a glance.
Sending one file per person is a data-protection move
The most common reason a spreadsheet leaks is not an attacker — it is sending the whole workbook when only twelve of its rows were meant for the recipient, and trusting a filter to hide the rest. Filters and hidden rows travel with the file.
Splitting by column value produces files that physically contain only the rows they should. That is a different guarantee from a hidden row, and it is the one worth having before an attachment leaves your outbox.
What you get back
- Every part is a proper CSV with the header row repeated, so each one opens cleanly on its own.
- Download parts one at a time, or take all of them as a single .zip — assembled in your browser, not on a server.
- There is also a one-workbook option: every part becomes a sheet in a single .xlsx, which is easier to hand to one person than a folder of files.
- Values that are blank in the chosen column are grouped into a file called
(blank)rather than being dropped — a silently discarded row is the worst possible outcome here.
When the split is a symptom
Splitting a file because a spreadsheet cannot hold it is treating the symptom. Excel stops at 1,048,576 rows per sheet, and people reach for a splitter when they cross it — there is a page about that.
TableDI 2 is a desktop app for file work you redo every period: it keeps your sources, rules and delivery as a job, so next month you drop in the new files and run it again. Everything runs on your own machine. Files past Excel's sheet limit still filter and export there, so a large monthly export does not need cutting up just to be checked and handed on.
Questions people ask
How do I split a large CSV into smaller files?
Drop it here, leave the mode on "into parts of N rows", set the number of rows you need per file, and take the zip. Each part carries the header row, so every file opens correctly on its own.
Can I split an Excel file into multiple files?
Yes — drop an .xlsx and the first sheet is used. The output is CSV parts, or a single .xlsx with one sheet per part if you prefer to hand over one file.
Can I split by a column such as region or month?
Yes. Switch the mode to "one file per value in a column" and choose the column. You get one file per distinct value, named after it, listed largest first.
Are my files uploaded anywhere?
No. The file is read by JavaScript running in this tab, using the browser's own
DecompressionStream to unzip .xlsx and a parser that runs on your machine. The page does load two visitor counters — static.cloudflareinsights.com and this site's own /_vercel/insights — but no request carrying your data appears in the network tab while you use it. Close the tab and the data is gone.
How large a file can be split here?
The file is held in memory while it is cut, so the limit is your machine's RAM rather than a row cap. Files of a few hundred megabytes are where a browser tab starts to struggle.
Related
Doing this every month?
In TableDI 2 you do it once, then save it as a job. Next month you drop in the new files and run it again.
macOS, Apple silicon and Intel; Windows is in progress (what to do meanwhile). Free is not a trial — no account, no card.
Last reviewed 2026-09-11 by the TableDI team. Something wrong on this page? Tell us — it is one inbox, read by the people who build TableDI.