Merge Excel Files
Processing entirely on your device — large files may take a moment.
Monthly reports scattered across twelve files, team budgets in separate workbooks — drop them in order and every sheet from every file lands in one workbook, first file first. Sheet names are preserved; when two files have the same sheet name, the second gets an automatic -2 suffix so nothing overwrites.
Formatting, formulas references within each sheet and multiple sheet tabs all survive — the merge is structural, not a flatten into one giant table.
How to merge Excel files
- 1
Select your files
Drag & drop your XLSX files onto the area above, or click to browse. You can add multiple files at once for batch conversion.
- 2
Convert instantly
Click "Convert to XLSX". The conversion runs entirely inside your browser using WebAssembly — no upload, no queue, no waiting.
- 3
Download results
Download each converted XLSX file individually, or grab everything at once as a ZIP archive.
About the XLSX format
XLSX is the modern Excel workbook (default since Excel 2007, same OOXML zip-package idea as DOCX). One file can carry multiple sheets, typed cells, formulas that recalculate, charts, conditional formatting and pivot caches — a small application, not just a table. LibreOffice, Google Sheets and WPS open it natively, and server-side libraries can read and write it without Excel installed.
Being a spreadsheet program's file, it is a poor plain-data exchange format: formulas reference cell positions that break when rows are reordered, hidden sheets and cached values surprise consumers, and the zip package is heavier than CSV. For analysis and finance it is the right tool; for pipelines, export the CSV.
+Strengths
- ✓Multi-sheet with formulas, charts and formatting
- ✓Typed cells and recalculation
- ✓Opens natively across the office ecosystem
!Limitations
- −Heavier and less diff-friendly than CSV
- −Formulas tie data to cell positions
- −Hidden state (sheets, caches) surprises downstream tools
Frequently asked questions
Will formulas still work after merging?
Formulas inside each sheet keep working. Cross-sheet references to other workbooks break (their targets are not in this file) — re-point those after merging.
Can I merge XLS and ODS files too?
Yes — XLS, XLSX and ODS inputs all merge into one standard XLSX output.
Is there a sheet or file limit?
No hard limit — Excel itself caps 255 sheets per workbook; browser memory is the practical ceiling for very large files.