CSV Splitter
Choose a large CSV, set how many rows per file or how many files, and download the parts as one ZIP.
Your file is split inside this page and never uploaded.
What this tool does
To split a CSV file, choose it, then set either the number of rows per file or the number of files. Keep the header option ticked and every part starts with the same header row. The parts are packed into one ZIP you download. Quoted fields with commas or line breaks are handled, and nothing is uploaded.
Parses the CSV into records, divides them into groups, and writes each group as its own CSV file.
Packs the files into a ZIP, named part-01, part-02 and so on, and lists them with their row counts.
How to use it
- Choose the CSV file.
- Choose Rows per file or Number of files, and enter the value.
- Leave "First row is a header" ticked to repeat it in every part.
- Check the list of files, then press Download ZIP.
Why use this splitter
Splits a CSV by rows per file or by number of files, and repeats the header row in every part so each opens on its own. Excel stops at 1,048,576 rows and many import tools reject large files. Splitting a big export into manageable parts - each with its header - lets you open, review and import it a piece at a time.
Why we built it
We built the CSV splitter to repeat the header row in every part, so each file opens on its own. Join files again with the merge CSV files tool and tidy them with the CSV formatter.
Who this tool is for
- Analysts with files too big for a spreadsheet
- Marketers splitting lists for import limits
- Developers batching data
When to use it
- A CSV is too big for Excel or Google Sheets to open.
- An import tool or API accepts only a limited number of rows per upload.
- Sharing a big list between several people to work on in parallel.
- Breaking a mailing list or product feed into batches.
How it works
The file is read as records, not lines, so a quoted field that contains a line break stays in one piece. With "Rows per file" the records are cut into groups of that size and the last file holds the remainder. With "Number of files" the rows are divided as evenly as possible.
When the header option is on, the first record is written at the top of every part and is not counted in the data rows.
Fields are written back with standard CSV quoting, so some files will differ in quoting from the original even though the data is identical.
What you give it, and what you get back
| Item | Details |
|---|---|
| Input | A .csv, .tsv or .txt file with a separator of comma, semicolon, tab or pipe. |
| Split by | Rows per file, or the number of files. |
| Header | Repeat the first row in every part, or treat all rows as data. |
| Output | A ZIP of CSV files with a list showing each file and its row count. |
Issues you may run into
| What you see | Why it happens | What to do |
|---|---|---|
| Everything is one column in the output | The wrong separator was detected. | Choose the separator manually and split again. |
| Too many files | The rows-per-file number is small for a large file. | Increase rows per file, or split by number of files. |
| Browser runs out of memory | The file is very large and is read whole. | Close other tabs, or use a desktop tool for files of several hundred MB. |
| A part has fewer rows than the others | The last part holds the remainder. | This is expected. |
Assumptions and limitations
- The whole file is read into memory, so very large files can fail on small devices.
- Output uses standard CSV quoting and the detected or chosen separator.
- It splits by row count, not by the value in a column.
Frequently asked questions
How do I split a large CSV file?
Choose the file, enter rows per file or number of files, and press Download ZIP. Each part is a CSV with its header.
Will each part have the header row?
Yes, when "First row is a header" is ticked, every part begins with it.
What is the best number of rows per file for Excel?
Anything under 1,048,576 works. For comfortable use, 100,000 or fewer rows per file is easier to work with.
Can it split a file with quoted line breaks?
Yes. Records are parsed properly, so a quoted cell containing a line break is not split.
Is my file uploaded?
No. The file is split in your browser.
Can I put the parts back together?
Yes - use the Merge CSV files tool to stack them again.