How to convert audio to MP3
- Choose one or more audio files (up to 20, each up to 200 MB).
- Pick the output: MP3, WAV, OGG or WebM, and a bitrate for the compressed formats. Tick Mono for speech to halve the size.
- Press Convert. Each file shows a player and a download button; with several files you can also download a ZIP.
Which format to pick
- MP3: plays on every phone, car stereo and app. The safe choice for sharing.
- WAV: uncompressed and lossless, for editing in audio software or uploading where quality matters. Large files.
- OGG and WebM: Opus audio, small files with good quality; they play in browsers, Android and VLC, but not every older device.
How big will the file be?
Compressed formats here use a constant bitrate, so the size is simply bitrate × length: kilobits per second ÷ 8 gives kilobytes per second. WAV stores every sample: sample rate × channels × 2 bytes.
Example
A 3-minute stereo song converted to MP3 at 192 kbps is 192,000 ÷ 8 = 24,000 bytes a second × 180 seconds = 4,320,000 bytes, about 4.3 MB. As a 44.1 kHz WAV it is 180 × 44,100 × 2 channels × 2 bytes = 31,752,000 bytes (about 31.8 MB), over seven times larger. At 96 kbps, Opus in OGG needs about 2.2 MB.
Tips
- Need only part of a song, for example a ringtone? Trim it first with the Audio cutter, which also saves MP3.
- To pull the sound from a video, you can drop the video here, or use Video to audio.
- Only convert audio you own or have permission to use.
MP3 files are encoded with LAME (lamejs 1.2.1, licensed under the LGPL-3.0), which is loaded unmodified as a separate file. Licence and source code.