Is my data secure on FileMerger?

Yes. Every row is processed locally in your browser using WebAssembly. Your data never leaves your computer.

Is FileMerger really free?

Yes, the tool is completely free. We support the site through subtle ad placements.

Merge Excel & CSV Files Instantly

Q: How many files can I merge?

There are no hard limits, but large datasets are limited by your computer's RAM. We recommend batches under 500MB.

100% Local Processing • No Uploads • Secure

Select multiple spreadsheets, merge them securely in your browser, and download the result.

Upload Files

Drag & Drop your files or Browse

Supported formats: .csv, .xls, .xlsx

No-Nonsense Tools for Your Data

Smart Header Detection

One file says 'Email', the other says 'E-mail'? Our engine figures it out so you don't have to rename columns manually.

Spot the Duplicates

Quickly identify double entries or unique identifiers before you finalize your merge. Clean data is happy data.

Excel-Ready Results

Download a clean, perfectly formatted .xlsx file. Ready for your pivot tables or CRM imports immediately.

Your Files, Your Privacy

We don't upload your data. Every byte is processed locally in your browser. It's safe, secure, and private.

Blazing Fast

Built for speed. Merge thousands of rows in the blink of an eye without your browser breaking a sweat.

How to Merge Excel & CSV Files Online

Drop Your Files

Select your files and drag them over. We don't care if they're messy—our engine handles .xlsx, .xls, and .csv all at once.

Align the Data

Headers don't match? No problem. Use our mapper to align 'First Name' with 'Name'. You direct the flow, we handle the merge.

Download the Master

Download a clean, unified Excel file. No duplicate headers or junk data—just what you need for your report.

Why Choose FileMerger?

100% Local Processing

Your data never leaves your computer. Period.

Blazing Fast

Process large datasets in seconds without waiting for uploads.

Free & Unrestricted

No sign-ups, no paywalls, and no annoying restrictions.

Frequently Asked Questions

Is my data actually safe?

Honestly, it's safer than most 'cloud' tools. We use WebAssembly to process every row directly in your browser. Your data never leaves your computer, and we never see it. Period.

What's the catch? Is it really free?

Yes. We keep the lights on with subtle ad placements, so you don't have to pay for a subscription. No hidden fees, no 'Pro' version locks.

How many files can I merge at once?

Since it runs on your machine, it depends on your RAM. For most computers, merging 50+ files (totaling under 500MB) works like a charm. If you have massive datasets, we recommend merging in smaller batches.