Use this Google Sheets add-on to convert Microsoft Office files to Google Docs, Sheets or Slides format.

If you have folders full of Microsoft Office files on your Google Drive and would like to convert them to Google format then this extension is for you.
Currently, the only way to convert files is by opening them individually and choosing to save as Google Docs or by downloading them and re-uploading with the auto convert option selected.  This extension will allow you to select individual files or entire folders on your Google Drive to convert in one go.

Current Limitations: Will only work on files up to 50MB in size.