Open .xlsb files free in your browser
Excel’s binary workbook format, used for large spreadsheets. Grid in Madosuite opens .xlsb files, in a browser tab, without Excel.

Three steps
Open Madosuite
In your browser. A small Linux machine starts on your device.
Upload the file
In Files, press Upload and pick your .xlsb file. Then open it with Grid.
Edit and save as
Save it as XLSX, CSV, TSV and download it.
Grid reads the worksheet data and saved values of an .xlsb, not its formulas. Save it as .xlsx or CSV.
Grid opens
Grid saves
Questions
How do I open a .xlsb file without Excel?
Open Madosuite in your browser, upload the file in Files, and open it with Grid. It is free.
Can I edit it and save it again?
You can edit it, then save it as XLSX, CSV, TSV, PDF. Grid does not write .xlsb itself.
Is my file uploaded?
No. It goes into the Linux machine that Madosuite runs in your browser, on your device.
Will it look the same?
Grid reads the worksheet data and saved values of an .xlsb, not its formulas. Save it as .xlsx or CSV.
Is Madosuite free?
Yes. The apps run on your own device, in the browser tab, so there is no server time to pay for. There is no trial period.