MP3 Converter

Turn almost any audio file, or the sound of a video, into an MP3 that plays on every phone, car stereo and music app. Most files are decoded by your browser and encoded with LAME right on your device, so nothing is uploaded and there is nothing to install. Variable bitrate, very long files and formats the browser cannot read use the ffmpeg engine, a one-time download of about 30 MB.

How to use this tool

1. Choose one or more files (WAV, M4A, FLAC, OGG, WMA, AIFF, video…).
2. Pick the quality: 192 kbps for music, 128 kbps for podcasts, or a VBR setting.
3. Optionally change the sample rate or switch to mono.
4. Press Calculate and download the MP3s, one by one or as a ZIP.

Formula

MP3 size (bytes) ≈ bitrate (kbps) × 1000 ÷ 8 × length (s)

Constant bitrate (CBR) spends the same number of bits on every second. VBR lets LAME spend more on busy passages and less on quiet ones; V0 averages about 245 kbps and V2 about 190 kbps. MP3 only exists at 8–48 kHz, and low sample rates have a lower bitrate ceiling (64 kbps at 8–12 kHz, 160 kbps at 16–24 kHz).

Example

A 3-minute song at 192 kbps takes 192,000 ÷ 8 × 180 = 4,320,000 bytes ≈ 4.1 MB. The same song at 128 kbps is about 2.7 MB, and a 30-minute mono podcast at 64 kbps about 13.7 MB.