Convert audio to MP3 — free online tool

Convert any audio file to MP3 with the LAME encoder at 96 to 320 kbps, choose mono or stereo and 22.05 to 48 kHz, in your browser.

Audio

Convert audio to MP3

Choose a file, adjust the edit, preview the result, and export it.

Or drop an MP3, WAV, M4A, AAC, FLAC, OGG, Opus, or WebM audio file anywhere on this page.

Processed audio will appear here.

What to know

MP3 is the format that plays everywhere: car stereos, old phones, podcast hosts, game engines and every browser. The converter encodes with the LAME library, which is the reference-quality encoder for the format, and writes audio/mpeg files.

The Audio quality menu offers 96, 128, 192, 256 and 320 kbps, and the preselected 192 kbps works for speech and most music. Bitrate is the total for the file, so a mono recording at 96 kbps spends the whole budget on one channel, which is why mono speech sounds better than stereo at the same setting.

The data rate is a plain multiplication: bitrate divided by 8 gives bytes per second. At 128 kbps that is 16,000 bytes per second, so a 45-minute interview weighs 2,700 s x 16,000 = 43.2 MB, and at 320 kbps the same interview grows to 108 MB.

MP3 supports 22.05, 32, 44.1 and 48 kHz among the sample rates offered, which fits the menu exactly. Source files from a WAV or FLAC at 96 kHz are brought down by choosing one of these values.

Because MP3 is lossy, going from FLAC or WAV to MP3 is a one-way trip. A file named interview.wav becomes interview-mp3.mp3, and the original stays untouched on your disk.

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How to use Convert audio to MP3 — free online tool
  1. Drop interview.wav or any supported audio file into the box; Export format is already set to MP3.
  2. Pick 128 kbps in Audio quality for a talk, or 320 kbps if you are archiving a music track you will not re-encode.
  3. Set Channels to Mono for a single-voice recording, and keep Sample rate on 44.1 kHz.
  4. Press convert, listen to the preview, and download interview-mp3.mp3.

Quick answers

What is the biggest MP3 bitrate I can pick?

320 kbps, which is also the highest rate the MP3 format allows. A 4-minute track then weighs about 9.6 MB.

Why is mono 96 kbps clearer than stereo 96 kbps?

The bitrate is shared across channels. A mono file gives all 96 kbps to one signal, while stereo splits it between two.

Which encoder produces the MP3?

LAME, the widely used open-source MP3 encoder, writes the audio at the bitrate you select.

Can I turn a 96 kHz file into MP3?

Yes, by choosing 48 kHz or lower in Sample rate. MP3 does not carry 96 kHz audio, so one of the offered values is needed.