Break a Large CSV into Several Smaller Files
Huge exports are awkward to attach to an email, push through an upload form with a size cap, or review on a laptop. Breaking the file into a handful of parts makes it easier to move around without changing what is in it.
Private by design. The parts and the zip are produced locally. Open a part or two before sending them on.
Steps
- Note any limit you need to meet, such as an upload cap in megabytes or a maximum line count.
- Load the file into the Split CSV tool.
- Pick a row count that should keep each part under that limit. If you only know a size cap, estimate from the average line length. The zip is not compressed, so it is roughly the size of the original file.
- Download the zip and unpack it.
- Send or upload the parts in order and mention how many there are, so nobody misses one.
Good to know
Delimiter and encoding
The parts keep the same separator as the source, whether comma, semicolon, tab or pipe, and keep a UTF-8 byte order mark only if the original had one. Each piece should then open the same way the full file did. A file that is not UTF-8 is copied byte for byte, so its accented letters stay intact, though file names built from its values show _ for them. When splitting by a column, a value made only of spaces gets its own file, separate from the file for empty values. Files that look binary get a warning but are still split.
Quoted fields
Cells wrapped in quotes can contain commas or even line breaks. The splitter treats such a cell as part of one row, so a record is not cut in half across two parts. Rows are copied exactly as they are, so open files from unknown sources with care.
Reassembling later
Because every part carries the header, they can be stacked back together. The free Merge and Clean CSV tool can help with that.
Questions
Why a zip instead of separate downloads?
One download is easier than dozens of prompts. The zip is built in your browser and is stored without compression.
Does the zip get uploaded somewhere?
No. The tool makes no network requests, so the file and the zip stay on your device.
Can I choose how parts are named?
Not in this version. Parts are named after your file with -part-001, -part-002 and so on.
Is there a size limit?
Output over 4 GB is refused, and very large outputs may run out of browser memory before that. The on-screen list shows only the first 200 files, but the zip contains every file.
Have bank statements as PDFs instead? RowSmith converts text-based PDF statements to CSV or Excel in your browser.
This guide was written with AI assistance and reviewed against the tool's behaviour. Always review your output before using it.
RowSmith is an independent tool and is not affiliated with any bank or software company.