Free HD Video Converter Factory is the best free MP4 to MP3 converter software available for Windows users. Thanks to its simple interface and smart features, it can make MP4 to MP3 conversion a breeze. Meanwhile, it offers options to adjust output setting to bring high-quality MP3 outputs, e.g. 320kbps MP3. Besides converting MP4 to MP3, this program also lets you fast convert MP4 or other videos to WAV, AAC, AC3, WMA, M4A, OGG, etc., effortlessly. It can also trim audio, merge music, compress large files, and download online videos.

Another amazing free MP4 to MP3 converter for Windows is 4Media MP4 to MP3 Converter. The software has got a very simple and intuitive interface so new beginners can handle it without much trouble. You can easily convert your wanted video files to various audio files, such as MP3, WAV, AC3, WMA, M4A, OGG, and AAC swiftly. Besides, it also supports multithreading and batch conversion, so the conversion speed is super-fast. Yet, the trial version only allows the utmost 3 minutes of every file to be converted, which holds a big turn-off for many users.

Format Factory is a classic multifunctional media processing tool on Windows that can perform various kinds of conversions among videos, audio, and picture files. And using the program to convert MP4 to MP3 is more than enough, just like many other converters. But what it outshines other rivals is its capability to batch convert up to four files, speeding the conversion process greatly. Other benefits of using Format Factory include super-easy operations, conversions for different needs, and DVD to digital backup. But keep in mind that Format Factory is ad-supported freeware. You might get unwanted software installed on your computer by a misclick on the ads.