MP4 to MP3 Converter

This free MP4 to MP3 converter extracts the audio track from any video file and saves it as a standard MP3. Drop in a recorded Zoom meeting, a YouTube download, a voice memo, a concert clip, or a podcast episode — FastConvert pulls out the audio in seconds and lets you pick the bitrate. The entire conversion runs in your browser using FFmpeg compiled to WebAssembly, so your video never leaves your device.

Why Extract Audio from Video?

• Listen offline on your phone — Turn a long lecture or webinar into an MP3 you can play in any music app during commutes or workouts.
• Save storage — An hour of MP4 video is typically 500MB–1GB. The audio alone as MP3 is 60–90MB. If you only need to hear it, MP3 is 10× smaller.
• Pull music from concert clips — Extract the audio from videos you recorded at a live show or a practice session.
• Podcast from video interviews — Convert a video interview into an audio-only version for podcast publishing.
• Transcription preparation — Most transcription services (Otter.ai, Rev, Whisper) work faster and cheaper with audio-only input.
• Use audio in a DAW — Import the MP3 into GarageBand, Logic, Audacity, or FL Studio without having to decode video.

Choosing the Right Bitrate

MP3 bitrate controls the trade-off between audio quality and file size. FastConvert lets you choose from four common settings:

• 128 kbps — Roughly 1MB per minute. Fine for spoken-word content (podcasts, lectures, interviews) where you don't need musical fidelity.
• 192 kbps — About 1.4MB per minute. The default — a good balance for most music and mixed content, and what most streaming services used before high-definition audio.
• 256 kbps — Roughly 1.9MB per minute. Noticeably clearer highs, recommended when the source is already high-quality music.
• 320 kbps — About 2.4MB per minute. The maximum MP3 bitrate. Only useful if your source video has lossless or very high-bitrate audio; otherwise you're wasting space.

Keep in mind: the audio quality of the MP3 is capped by the audio quality of the source video. Converting a 128 kbps AAC track at 320 kbps MP3 does not restore lost quality; it just makes a bigger file.

Supported Input Formats

This converter accepts MP4, MOV, WebM, AVI, MKV, and M4V video files. If you have a less common format, use our universal converter to transcode to MP4 first. The tool re-encodes the audio (not just remuxing), so you get a clean, standardized MP3 regardless of what audio codec the source video used — AAC, Opus, Vorbis, AC-3, and others all work.

Trimming and Fading

Enable the Trim audio option to set start and end timestamps before extraction. Use the inline video player to find the exact moment to cut — useful when you only need a chorus, a specific quote, or a segment of a long recording. This also shrinks the output file proportionally.

When Not to Use MP3

MP3 is universal but not the most efficient codec available in 2026. If you're targeting a specific use case, consider: AAC (M4A) for Apple ecosystem and better quality at the same bitrate, Opus for messaging and podcast streaming (40% smaller at the same quality), WAV/FLAC for editing or archival where you cannot accept any quality loss. Use our MP4 to WAV or MP4 to AAC tools for those.