How do I combine Excel files into one workbook?

Upload your Excel or CSV files to Master Merge's Excel merger and click Merge. Each file becomes its own sheet inside a single downloadable .xlsx workbook.

Can I merge XLS, XLSX, and CSV in the same operation?

Yes. Mix and match any of these formats freely. The output is always a modern .xlsx workbook.

Will my formulas still work?

Formulas inside each sheet are preserved. Cross-file references are converted to plain values since the original files are now separate sheets.

Are merged sheets named clearly?

Yes. Sheets are auto-named based on the original filenames so it's easy to tell which data came from where.

Are my files uploaded to a server?

No. Master Merge processes every file directly in your browser using JavaScript. Nothing is uploaded, stored, or transmitted to any server. This is the most private way to handle sensitive documents online.

Does it work on mobile and tablets?

Yes. Master Merge runs in any modern browser including mobile Safari, Chrome, Firefox, and Edge on iOS, Android, Windows, macOS, Linux, and ChromeOS.

Is this tool really free?

Yes — 100% free with no signup, no credit card, no email, no watermarks, and no hidden limits. We do not run ads or sell data. Use it as much as you want.

Merge Excel Files

Combine multiple spreadsheets into a single Excel workbook.

Drag & drop your files here

or click to browse

XLSXCSV

Max 100MB per file · Up to 20 files

Supported Formats

XLSXLSXCSV

Merge Excel spreadsheets and CSV files online for free. Master Merge combines your workbooks into a single file, keeping each file's sheets organized. All processing happens locally in your browser using SheetJS technology.

How it works

Upload

Drag & drop or browse your files

Process

Files are processed in your browser

Download

Get your merged/converted file instantly

About Merge Excel Files

Master Merge combines multiple Excel workbooks and CSV files into a single .xlsx file. Each input file becomes its own sheet, keeping your data cleanly organized and easy to navigate. It's perfect for consolidating monthly reports, combining department spreadsheets, or merging exported CSVs.

The tool runs locally using SheetJS, so your spreadsheets never touch a server. Formulas, formatting, and column widths from the original files are preserved on each sheet. Sheet names are auto-generated from the source filenames so you always know which data came from where.

Just drag your .xlsx, .xls, or .csv files in, set the order, and download a unified workbook. There are no file size limits beyond your device's memory, no daily caps, and no watermarks.

Why use Master Merge for merge excel files

Each file becomes its own sheet for clean organization
Supports XLS, XLSX, and CSV inputs
Preserves formulas, formatting, and column widths
Auto-named sheets from source filenames
100% private — runs in your browser

Common use cases

Consolidate monthly sales reports into one workbook
Combine departmental budgets into a master file
Merge exported CSV data from multiple sources
Bundle student grade sheets across classes