Short answer: Choose MP4 if you want the video. Choose MP3 if you only want the audio.
What is MP4?
MP4 is a video container format that holds both a video track and an audio track together in one file. It is the most universally compatible video format — it plays on every device, platform, and media player.
When you download a YouTube video and want to watch it on your phone, laptop, or TV — MP4 is what you want.
What is MP3?
MP3 is an audio-only format. It strips out all video data and keeps only the sound. The file is much smaller — often 10–20× smaller than the same content as MP4.
MP3 is ideal for music, podcasts, lectures, speeches, or anything where you only need to listen — not watch.
Side-by-Side Comparison
Other Formats Explained
Like MP3 but slightly better quality. Common from YouTube and Apple devices. Use this if you want the best audio quality.
Open-source video format by Google. Smaller than MP4 at similar quality. Best for web playback in Chrome.
Open audio format. Similar to MP3. Less common but useful for certain platforms and older Android devices.
Tip: In FreeMake Downloader, after processing a URL switch to the Audio tab to see MP3 and M4A options. The Video tab shows all MP4/WebM options.