Split a large CSV into smaller files by rows, files, size or column value, header in each
Processed in your browser. Nothing is uploaded. Checked against sources on 16 Oct 2026.The CSV Splitter cuts a large CSV into smaller files in your browser, by rows per file (1,000 by default), by number of files, by megabytes or by a column's value, and repeats the header row at the top of every part. Files up to 1 GB work, nothing is uploaded, and the parts download as one zip.
Press Select a CSV, or drop the file on the page; it is read on your device and its rows are counted.
Choose how to split: rows per file (1,000 by default), a number of files, megabytes per file, or one file for each value of a column.
Keep First row is a header on to repeat the header at the top of every part.
Press Split, and the parts download together as one zip.
A CSV of a few hundred megabytes is common for exports from databases, analytics and online shops, and too big for many places it has to go: Excel opens at most 1,048,576 rows, Google Sheets 10 million cells, and upload forms often stop at 10 or 25 MB. Splitting it is the usual fix.
Four ways to split.
| Split by | Use it when |
|---|---|
| Rows per file | a system imports at most a number of rows at a time |
| Number of files | you want equal parts, for example one per person |
| Megabytes per file | an upload or email has a size limit |
| Column value | each region, branch or month needs its own file |
By column value. Every row goes to the file for its value in the chosen column, such as sales-North.csv, with rows kept in their order. Values are matched exactly, so North and north make two files; an empty value goes to a file named blank.
The header. With First row is a header on, the first line is copied to the top of every part and not counted as a row, so each part opens on its own with the right column names.
Nothing in the data changes. The file is cut between records, never rewritten. A record ends at a line break that is not inside double quotes, as RFC 4180 defines it, so an address with a line break in a quoted field stays in one piece. The delimiter, the quoting, the line endings and the encoding are kept byte for byte, and a UTF-8 byte-order mark is copied to every part so Excel still shows accents and other scripts correctly. UTF-16 files have to be saved as UTF-8 first.
On your device. The file is read by your browser and never uploaded. Parts are named after the file, such as sales-part-001.csv, and downloaded together in one zip. Up to 10,000 parts.
Every split was checked by reading the original and each part with Papa Parse, a separate CSV reader, and comparing the rows.
Drop the CSV on the CSV Splitter, choose rows per file, a number of files, megabytes per file or one file per value of a column, and press Split. The parts download as one zip, named like sales-part-001.csv, each with the header row. Files up to 1 GB are split in the browser.
Excel shows at most 1,048,576 rows per sheet and cuts the rest off. Split the file into parts of 1,000,000 rows or fewer, with the header kept in each, and open the parts one by one or import them into separate sheets with Power Query.
No. The splitter cuts the file between records and copies every byte of each record as it was: delimiter, quotes, line endings and encoding. Quoted fields with line breaks stay whole, because a line break inside double quotes does not end a record under RFC 4180.
Yes, when First row is a header is switched on, which it is by default. The header is copied to the top of every part and is not counted in the rows per file, so a part of 1,000 rows holds 1,001 lines. Switch it off for files without a header.
Parts are cut between rows, never inside one, so a part stops at the last whole row that fits. Splitting by number of files makes parts with the same number of rows, which can differ in megabytes when some rows are longer than others.
No. The file is read and split by your own browser, and the zip is built on your device. Nothing is sent to a server, which matters for customer lists and other personal data. Close the tab and nothing remains.
Rates and rules change; check the source before you rely on a figure.
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