Developer / Data
Split CSV: Rows per File or Number of Files
Split a large UTF-8 CSV into smaller files by row count or a chosen file count. Keep the header in every file and download the results together as a ZIP.
Split CSV: Rows per File or Number of Files: Reads CSV in chunks and preserves quoted records containing commas or new lines. Rows-per-file mode makes consecutive parts; number-of-files mode balances data rows across non-empty files. The first record can be repeated as a header. Record endings are written as CRLF. ZIP output is stored without compression. Limits are 1 GiB input, 16 MiB per record and 1,000 output files. Runs 100% locally in your browser with zero server file uploads.
- Category
- Developer tools
- Runs
- In your browser
- Cost
- Free · no sign-up
- Availability
- Ready to use
Runs entirely in your browser
Quoted fields can contain commas and new lines. Blank records are kept. Record endings are written as CRLF; text inside quoted fields stays unchanged. Number-of-files mode makes two passes and balances the row counts; fewer records than requested files produce fewer non-empty files.
Files are read in chunks. Output files and the ZIP still need browser memory. Limits: 1 GiB input, 16 MiB per record and 1,000 output files. ZIP entries are stored without compression.
CSV records
RFC 4180 documents CSV quoting, embedded new lines and optional headers (https://www.rfc-editor.org/rfc/rfc4180). The splitter counts logical records rather than physical lines.
ZIP and local files
PKWARE publishes the ZIP format specification (https://support.pkware.com/pkzip/appnote). The output uses stored ZIP entries with CRC-32 checksums. The W3C File API (https://www.w3.org/TR/FileAPI/) describes local file and Blob handling. Input stays on your device.
How to use it
- Choose a UTF-8 CSV file and a split method.
- Set the row count or file count, and choose whether the first record is a header.
- Split the file, inspect row counts and download the ZIP.
Privacy & limitations
Your inputs and files are processed in your browser. Nothing is uploaded.
Related tools
Frequently asked questions
Does a quoted new line count as a row?
No. A new line inside a quoted field belongs to that field. Only record boundaries outside quoted fields count as rows.
Are files balanced when I choose a file count?
Yes. Ten data records split into three files produce 4, 3 and 3 records. If there are fewer records than requested files, only non-empty files are produced.
Are blank records kept?
Yes. Blank records are counted and kept. The optional header is the first record, even if it is blank.
Is the full file read into a text box?
No. Input is read in chunks, and number-of-files mode makes two passes. Output files still occupy browser memory, so available memory can limit large downloads.
Free tool · runs in your browser · no account required