Split a List into Chunks

How to split a list

Paste your list into the box, one item per line, or press Open file to load a .txt or .csv file. Then choose how to split it:

• Lines per chunk cuts the list into chunks of that many lines. The last chunk gets what is left.
• Number of chunks shares the list out into that many parts, as evenly as possible.
• Take the first N lines gives you two parts: the first N lines and the rest.

Each chunk gets a card with Copy and Download buttons, and Download all (.zip) saves every chunk in one ZIP file. Lists under 200 KB update as you type; for bigger ones, press Split. Everything runs in your browser, so the list never leaves your computer.

What the options do

• Skip empty lines (on by default) drops blank lines and lines that hold only spaces.
• Trim spaces removes spaces and tabs at both ends of each line.
• Remove duplicates before splitting keeps the first copy of each line, so chunk sizes count unique lines. Matching is exact and case-sensitive. To ignore case or spacing, clean the list first with Remove Duplicate Lines.
• File name prefix and File type set the names. With 10 or more chunks the numbers are zero-padded (part-01 to part-13) so the files sort in order.

The options apply in that order, then the list is split. Line numbers on the cards refer to your original input, so a chunk can span more input lines than it holds when lines were skipped.

Examples

How the even split works

With Number of chunks, the tool divides the line count by the number of chunks. Every chunk gets the whole-number result, and the remainder is handed out one line at a time from the first chunk on. For 10 lines in 3 chunks, 10 ÷ 3 is 3 with 1 left over, so the chunks get 4, 3 and 3 lines. No two chunks differ by more than one line, and the order of lines never changes. Ask for more chunks than there are lines and you get one chunk per line instead of empty files.

Repeating a CSV header

A CSV file's first line usually names the columns, and chunks without it are hard to import. Turn on Repeat the first line in every chunk and the first line is added to the top of every chunk. It is not counted toward the chunk size: 1,000 lines per chunk gives 1,000 data rows plus the header. With duplicate removal on, later copies of the header are dropped, which helps when several exports were pasted together (or combine the files first with Merge Text Files).

The tool splits on line breaks and doesn't parse CSV, so a quoted field that contains a line break can be cut across two chunks. Check the chunk edges if your data has multi-line fields.

Why split a list

• API batch limits. Many APIs cap the items per request. IndexNow, for example, accepts up to 10,000 URLs per POST request, so 35,000 URLs take four requests.
• Import limits. Ad platforms, email tools and CRMs often limit the rows or file size per upload. Check the current limit in their documentation and pick a chunk size just under it.
• Sitemaps. One sitemap file can list at most 50,000 URLs, so split bigger lists into chunks of 50,000 and make one sitemap per chunk.
• Spreadsheets. Google Sheets limits the total number of cells in a spreadsheet (Google began raising it from 10 million to 20 million in September 2026), so a wide CSV hits it sooner than a narrow one. Excel allows 1,048,576 rows per worksheet.
• Work that runs one item at a time. The URL Inspection tool in Google Search Console checks one URL at a time, and its API allows 2,000 inspections per day per property, so chunks of 2,000 give you one batch per day. To share a list among a team, pick Number of chunks and give each person a file.

Limits and edge cases

You can open files up to 20 MB. The page shows the first 200 chunks; the ZIP holds all of them, up to 65,535 files (the limit without ZIP64), uncompressed. Files are read as UTF-8, so resave older CSV exports as UTF-8 if accented letters look wrong. Windows (CRLF) line endings are kept, and each downloaded file ends with a line break.

Command-line equivalents

On Linux and macOS, split does the lines-per-chunk mode:

split -l 1000 file.txt part-

This writes part-aa, part-ab and so on. GNU split (on Linux) adds -d for numbered files and --additional-suffix=.txt for an extension. Its -n l/5 option makes 5 files without breaking lines, but it balances bytes rather than lines, so line counts can differ. For the first N lines, use head -n 100 file.txt and tail -n +101 file.txt. To repeat a CSV header:

tail -n +2 data.csv | split -l 1000 - rows-
for f in rows-*; do (head -n 1 data.csv; cat "$f") > "$f.csv"; rm "$f"; done