Compress Excel makes .xlsx files smaller by shrinking the pictures and logos inside, removing the saved preview picture and packing the file tighter. Your data, formulas, charts and formatting are not changed.
No. The file is opened and changed inside your browser, on your phone or computer. Nothing is sent to our servers.
Files without pictures are mostly text, which is already compressed. Large savings come from images inside the workbook.
Convert it with XLS to XLSX first.
Yes. Compress Excel works inside your browser. Your files are not uploaded anywhere, so nobody else can see them, and there are no waiting queues.