How long does MP4 to MP3 conversion take?

For most files, conversion takes 2–10 seconds regardless of the video length, because FFmpeg only processes the audio stream. A 1-hour MP4 file converts to MP3 in roughly the same time as a 5-minute file. The processing time depends on your device's CPU speed, not the video duration.

Will the MP3 quality match the original MP4 audio?

At High (320 kbps), the MP3 output is indistinguishable from the original for the vast majority of listeners. If the source MP4 has a 128 kbps AAC audio track, exporting at 320 kbps won't improve it — the original quality is the ceiling. Standard (192 kbps) is the ideal setting for most MP4 files, balancing file size and quality.

Does this work for screen recordings?

Yes. Screen recordings from OBS, macOS Screen Recording, Windows Game Bar, or any other tool are typically MP4 files. The audio track (system sound, microphone, or both) is extracted exactly. For recordings with both system audio and microphone on separate tracks, FFmpeg selects the default mixed track.

Can I extract audio from a 4K MP4 file?

Yes. File resolution does not affect audio extraction speed or quality. The video resolution is completely ignored — only the audio stream is processed. A 10 GB 4K video converts to MP3 just as quickly as a 100 MB 720p video.

MP4 to MP3 Converter

Convert MP4 to MP3 online for free in your browser. Extract audio from MP4 files — no upload, no account, instant download.

Drop your video here

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MP4, MOV, AVI, MKV, WebM, WMV, FLV and more · up to 2 GB

Output Settings

Output Format

Bitrate

MP4 to MP3 is the most common audio extraction task on the web. MP4 files contain both video and audio tracks; MP3 conversion strips the video and re-encodes just the audio at your chosen bitrate. Common use cases include extracting background music from a video clip, converting a movie soundtrack to listen on the go, saving a conference recording as a podcast-style audio file, or pulling vocals from a video message. Unlike online services that require uploading to a server, Zolkit processes your MP4 entirely inside the browser. There are no file size limits, no waiting in a queue, and your video content stays completely private. The extraction itself takes seconds — FFmpeg reads the MP4 container, decodes the AAC or MP3 audio track, and re-encodes it to your chosen bitrate. For most MP4 files from cameras, screen recorders, or social platforms, Standard quality (192 kbps) produces an MP3 that is perceptually identical to the source audio on any playback device.

Related Use Cases

← Audio Extractor MOV to MP3 Converter Online Extract Audio from Video Online

Free Online Audio Extractor — Convert Video to Audio in Your Browser

Zolkit's Audio Extractor uses FFmpeg WebAssembly to extract audio from video files entirely in your browser. Upload MP4, MOV, AVI, MKV, WebM, or WMV files and extract the audio track as MP3, AAC, WAV, FLAC, or OGG — without sending your file to any server. Choose 320 kbps for archival quality or 192 kbps for a smaller file that sounds identical on speakers and headphones. All processing happens locally on your device — your videos never leave your browser.

100% Private

Your video never leaves your device. All extraction runs in WebAssembly inside the browser tab — no server, no cloud, no data retention.

5 Output Formats

Choose MP3 for universal compatibility, AAC for Apple devices, WAV or FLAC for lossless archival, or OGG for web and open-source projects.

Quality Control

Three MP3/AAC/OGG bitrate presets — 320 kbps (high), 192 kbps (standard), 128 kbps (low). WAV and FLAC are always lossless.

FFmpeg-Powered

Uses FFmpeg's audio demuxer and libmp3lame encoder — the same pipeline used by professional audio and video tools worldwide.

Free, No Account

No subscription, no sign-up, no watermark, no file size cap beyond your device's memory. Zolkit's Audio Extractor is completely free.

Any Video Format

Supports MP4, MOV, AVI, MKV, WebM, WMV, FLV, M4V, 3GP, TS, and most other video containers. If FFmpeg can read it, you can extract from it.

How to Extract Audio from a Video

1
Upload your video — drag it onto the page or click to browse. Supports MP4, MOV, AVI, MKV, WebM, WMV, FLV and more up to 2 GB.
2
Choose output format (MP3, AAC, WAV, FLAC, or OGG) and quality (bitrate for lossy formats). MP3 at 192 kbps is the best default for most uses.
3
Click 'Extract Audio', wait a few seconds for processing, then preview the file size and download the extracted audio.