Put several .xlsx, .xls, or .csv files into one workbook, keeping every sheet. All in your browser.
No sign-up and nothing uploaded to a server: everything happens in your browser. See for yourself.
No. Everything is processed inside your browser, and your files never leave your device.
No. It creates one workbook with all the sheets; each one stays separate.
Yes, each CSV becomes a sheet.
Each sheet from each file is added as a sheet in the new workbook, named after the file so you can tell them apart.
Values and formulas are kept. Some special formatting, charts, or macros may not carry over to the new workbook.
This tool combines sheets; it doesn't merge the rows of several tables into a single sheet.