Free Bulk CSV Merger & Splitter

Combine lots of CSV exports into one file, with columns lined up by name even when they're in a different order. Or break a huge CSV into smaller files that Excel or an upload form will accept. Everything happens in your browser.

Quick human check, then the tool unlocks:

Drop CSV files or whole folders here Any delimiter and encoding: they are detected for you.

Columns Add a column with the file each row came from Remove duplicate rows

Save with Encoding

How to merge or split CSV files

Choose Merge or Split, then drop in your CSV files or press Choose a folder.
For merging, choose how columns line up. For splitting, choose rows per file or a column to split by.
Press the button and download the result.

🔒 Your files are processed by your own browser and are never uploaded to our server.

Examples

Monthly exports: merge twelve monthly order CSVs into one year, even if a column was added halfway through.
Upload limits: split a 300,000-row contact list into files of 10,000 rows for an email service.
One file per region: split by the "State" column to get a CSV for each state.