About Merge Excel Files Online
A browser-based tool for combining spreadsheet files without uploading workbook contents to a spreadsheet-processing server.
Last updated: 25 September 2026
What the service does
MergeExcelFilesOnline.com combines XLSX, XLS, XLSM, XLSB, CSV, TSV and ODS inputs and downloads an XLSX or CSV result. It is useful for consolidating exports, recurring tables and workbook tabs without installing a separate desktop merging application.
Three merge modes
Append Rows stacks data from the first worksheet of each file and aligns columns by header. Side-by-Side Columns places data from each first worksheet in parallel blocks. Preserve Sheets carries source worksheets into separate destination worksheets.
Optional formatting
Keep original formatting is an independent option and starts off. It is available only when every input and the output are XLSX. It can retain supported formatting and structures in all three modes, while unsupported advanced structures can stop the operation without producing partial output. Leave it off to use the compatibility route.
Browser processing and limits
Workbook processing happens in the browser. Normal hosting, asset and disclosed Google Analytics requests still occur. Formatting-aware processing downloads a same-origin browser Worker and WebAssembly module and enforces package, resource, cell, column and time limits. The browser does not calculate formulas, and the tool does not execute macros.
Contact and policies
Use the Contact page or [email protected] for support and privacy questions. The Privacy Policy explains website data handling, the Terms describe use of the service, and What’s new records important product changes.