CSV Splitter
Split a CSV too large for Excel into parts. Free, no signup, no upload.
Excel's limit is 1,048,576 rows including the header row.
Parts are cut between rows, so each one stays at or just under this size (1 MB = 1,000,000 bytes).
Parts are always written as UTF-8.
| Part | Data rows | Size |
|---|
How It Works
Pick a CSV file and choose how big each part should be. The file is read in small pieces as a stream, so a multi-gigabyte export does not have to fit in memory. A quote-aware parser tracks whether it is inside a quoted field, so a line break inside quotes (an address or a comment, for example) stays in its record. Parts are cut only between complete records.
The header row is written at the top of every part, and each part gets a UTF-8 byte order mark so Excel reads accented characters correctly. The parts are then packed into a ZIP, offered as separate downloads, or written straight into a folder you choose. Nothing is uploaded.
Not sure why Excel cut your file short? Read CSV too large for Excel.
Why Excel Needs the File Split
Microsoft's Excel specifications and limits page puts a worksheet at 1,048,576 rows by 16,384 columns. When a CSV has more lines than that, Excel loads what fits and warns that the data set is too large for the grid. Microsoft also warns that if you save over the original file, the rows that were not loaded are lost. Keep the original and split a copy instead.
The default of 1,000,000 data rows per part leaves room for the header and stays under the grid limit. Choose a size in megabytes instead if you are splitting for an upload limit or an email attachment.
Output Options
| Option | Best for | Limits |
|---|---|---|
| One ZIP file | Most files; one download | ZIP up to 4 GB; built in memory |
| Separate CSV files | A few parts you want one by one | Parts kept in memory until saved |
| Save into a folder | Multi-gigabyte files | Chrome or Edge on a desktop |
Other limits: parts are written as UTF-8 whatever the input encoding, line endings inside records are copied unchanged, and a file with a quote that never closes is reported because everything after it looks like a single field.
Frequently Asked Questions
How many rows can Excel open from a CSV?
An Excel worksheet has 1,048,576 rows by 16,384 columns, according to Microsoft's Excel specifications and limits. If a CSV has more lines than that, Excel loads the first 1,048,576 and leaves out the rest, so the file needs to be split to see everything in Excel.
Will rows with line breaks inside a cell be split in half?
No. The splitter reads the file with a quote-aware parser, so a line break inside a quoted field stays part of its record. Parts are only cut between complete records, never in the middle of one.
Is the header row copied into every part?
Yes, by default. With 'First row is a header' ticked, the first record is written at the top of every part, so each part opens in Excel with its column names. Untick it if your file has no header row.
Why is a byte order mark (BOM) added to each part?
Excel opens a CSV with a UTF-8 BOM as UTF-8, so accented letters and other non-English characters display correctly. Without it, Excel may show text such as é instead of é. You can switch the BOM off if another program needs the parts without it.
How large a file can it split?
The file is read in a stream, so it never has to fit in memory as a whole. The output is the limit: a ZIP download can be up to 4 GB, and separate-file downloads are held in browser memory until you save them. For multi-gigabyte files, Save into a folder (Chrome and Edge on desktop) writes each part straight to disk.
Is my CSV uploaded anywhere?
No. The file is read and split by JavaScript in your browser. Nothing is uploaded, which matters for customer lists, exports and other private data.