Word 97 (.doc) to OpenDocument text
Convert a .doc file to .odt. Free, no signup, and the file is deleted when the request ends.
Convert Word 97 (.doc) to OpenDocument text
Free, no signup, no credit charged. One file at a time.
This one sends your file. The converters are pandoc, LibreOffice and calibre, and none of them runs in a browser. Your document is converted in memory and deleted when the request ends — nothing is written to disk, logged or kept.