Convert to and from MP3, free.
MP3 is the universal audio format. It is lossy, so it throws away detail you are unlikely to hear, and in exchange the file is small enough to email and playable on absolutely anything.
Convert something else to MP3
Pick what you have. Each page opens the editor with MP3 already selected as the output.
Convert MP3 to something else
Pick where it is going. Lossy, so it is not the right master format for further audio editing.
What MP3 actually is
MPEG audio layer III
MP3 (lossy)
Podcasts, voice notes, music you need to send
Every device made in the last 25 years
Roughly a tenth of uncompressed audio
Plays on every phone, car stereo, browser and podcast host in existence.
Small enough to attach to an email or send in a chat.
Accepted by every transcription and podcast service.
Lossy, so it is not the right master format for further audio editing.
No support for multiple tracks or lossless quality.
Questions about MP3
What is an MP3 file?
MP3 is the universal audio format. It is lossy, so it throws away detail you are unlikely to hear, and in exchange the file is small enough to email and playable on absolutely anything. It is the MPEG audio layer III container, usually holding MP3 (lossy).
Is converting MP3 free?
Yes. Convert and preview for free, then create a free account to download the result. Nothing is installed and there is no watermark on the file itself.
Will converting to MP3 lose quality?
Some, whenever the codec changes: every re-encode discards detail. Where the container can simply be rewritten around the existing streams it is lossless, and where it cannot the default settings are chosen so the loss is not visible at normal viewing size.
Other formats
Converters
Convert it, then keep editing.
Every converter opens the full editor, so you can trim, caption and share without uploading the file twice.