Split a CSV file into smaller CSV files

Break one large CSV file into smaller CSV files—by rows per file or by a target number of files. Keep the header row in every part, preview the output filenames, and download a single CSV or a ZIP of parts.

Your CSV file is processed locally in your browser and is not uploaded to our servers.

How to split a CSV file

1. Choose or drag a .csv file into the tool.
2. Leave "First row contains headers" checked, or uncheck it if the file has no header row.
3. Choose Rows per file or Number of files, and set the value.
4. Review the proposed output filenames (and ZIP name when splitting into more than one file).
5. Select Split to create and download the CSV file or ZIP.

Browser-based CSV splitting

• Supported format: CSV.
• Splitting into one output file downloads a single CSV file.
• Splitting into two or more output files downloads one ZIP of CSV files.
• Quoted fields, delimiters inside quotes, escaped double quotes, embedded line breaks, empty cells, trailing empty columns, and Unicode content are preserved from the original record text—splitting does not re-encode your CSV.
• Splitting operates on the CSV record text directly; it does not pass your data through a spreadsheet library.

Private CSV splitting

Your CSV file is processed locally in your browser and is not uploaded to our servers. Parsing and file generation happen in the browser. ZIP packaging uses JSZip locally. There is no Looty Tools conversion endpoint that receives your CSV contents for this workflow.

Limits and important notes

• Maximum file size is 25.0 MB.
• A split cannot generate more than 200 output files. Requesting a file count greater than the number of data rows, or settings that would exceed the limit, is rejected with a clear message rather than silently reduced.
• "First row contains headers" is on by default. Turn it off for CSV files that have no true header row, or the first data row will be treated as a header and repeated in every output file.
• A CSV with only a header row and no data rows cannot be split while headers are enabled.
• Malformed CSV, such as an unterminated quoted field, is rejected before any split is attempted.
• Values are not re-typed or reformatted—this tool copies original record text, unlike CSV to Excel or Excel to CSV, which parse through a spreadsheet library.

Related tools

• CSV to ExcelConvert CSV files to Excel spreadsheets.
• Split ExcelSplit an Excel workbook into separate files.
• Excel to CSVConvert Excel spreadsheets to CSV files.

Split CSV FAQ

How do I split a CSV file?

Open Split CSV, choose a .csv file, pick Rows per file or Number of files, set the value, then select Split to download one CSV or a ZIP of CSV files.

Is my CSV file uploaded?

No. Your CSV file is processed locally in your browser and is not uploaded to our servers.

What is the difference between Rows per file and Number of files?

Rows per file creates as many output files as needed so each one holds the row count you set, with the remainder in the last file. Number of files creates exactly that many outputs and spreads the data rows across them as evenly as possible without creating an empty file.

Does the header row get repeated in every file?

When "First row contains headers" is checked (the default), the first record is treated as a header and repeated verbatim in every output file, and it is not counted as a data row. When unchecked, the first record is treated as normal data and is not repeated.

What happens if my CSV has no header row?

Uncheck "First row contains headers" before splitting. Leaving it checked on a file with no true header would remove and repeat what is actually a data row, so review the first row before you split.

Are quoted commas, quotes, and line breaks inside fields preserved?

Yes. Splitting works on the original CSV record text rather than re-encoding it, so quoted fields, delimiters inside quotes, escaped double quotes, and line breaks inside quoted fields are copied through unchanged.

What is downloaded?

A split that produces one output file downloads a single .csv file. A split that produces two or more output files downloads one ZIP containing each part as a separate .csv file.

How are the output files named?

Files are named after your original file with a part number, for example customers-part-1.csv, customers-part-2.csv, and so on. A multi-file ZIP is named after the original file too, for example customers-split.zip.

What are the size and output limits?

Each CSV file must be 25 MB or smaller, with an output ceiling of 200 files per split. Settings that would push past that ceiling, or a file count higher than the number of data rows available, produce a validation message instead of an automatically reduced split.

What happens with malformed CSV, like an unterminated quote?

The file is rejected with an error before any split is attempted. Fix the unterminated quoted field in the source file and try again.