About FileMerger
A free tool for combining spreadsheets, built by people who got tired of uploading confidential data to strangers.
Why This Exists
The job comes up constantly. Thirty monthly exports that need to become one annual sheet. A dozen CSVs from different regional systems, each with slightly different column names. An export from a CRM that arrives split across four files because someone set a row limit years ago and nobody remembers why.
Every existing option was unappealing. Online mergers wanted the files uploaded to a server in an unnamed jurisdiction, which is a straightforward policy violation in most companies that handle customer data. Desktop software meant a procurement request and a licence. Writing a script each time worked, but it is a poor use of an afternoon and it does not help the colleague who needs the same thing next week.
That's why I built FileMerger. I wanted a tool that actually works, costs nothing, and most importantly, stays 100% inside your browser. Your data never leaves your computer—because that's how software should work in 2024.
Privacy Is Not a Feature Here
It's the foundation. We don't "clear your data after 24 hours"—we never touch it in the first place.
What We Optimise For
Local by Default
There is no upload endpoint to secure because there is no upload. Your files are read from disk, processed in the browser sandbox and written back out. Open the Network tab and confirm it yourself.
Fast on Real Files
Skipping the round trip to a server removes the slowest part of the job. Merging a few hundred thousand rows finishes in seconds because the data never has to travel anywhere.
Free, and Honest About Why
The core merging tools are free and will stay that way. The site is funded by unobtrusive display advertising, which is why you see ads rather than a paywall or a request for your email address.