The Offline MethodThis can be done by simply opening the file in a program that could open docx files then saving it in the doc format. This is useful when you need to send the file to someone who has no application that could open docx file or when you need to take this file and run it on some other machine that may or may not have any such application.
How to Convert docx to doc Online
DOCX ConverterDOCX Converter is an online tool that can convert your docx file to various formats, one of which is the doc format. You just need to upload you file, enter your email and they will email you back with the converted file. This is the best tool for converting docx to doc.Link : DOCX Converter
ZamzarZamzar is another online tool that converts almost anything. It supports a very wide range of formats details of which can be found here. You can convert text, images, videos from any format to another. And obviously it converts files from docx to doc format and vice versa too. Just upload your file and you will get a file converted into the format you choose in your inbox. Zamzar has a limitation of 100 MB for the maximum size of the file which is not really a big issue while dealing with document files.Link : Zamzar
YouCovertItYouConvertIt is again an online conversion tool supporting wide range of formats for documents, images, audio and video. This has a limitation of 60 MB per file for a free unregistered user, and is increased to 100 MB if you register at their site with a free plan. You can get a paid plan if you want to convert files greater than the applied limit. YouConvertIt also provides a 200 MB free storage if you register with a free plan, that way you can store your files on their servers.Link : YouConvertIt
VerdictAll the above stated tools convert docx files to doc format online. It’s your personal preference which one you choose.