Convert M4A, AAC and other audio files to MP3 at 64 to 320 kbps. The file is processed inside your browser and never uploaded to a server.
Shrink a heavy PCM WAV into an MP3 without uploading it, turning a file too big to email into a normal attachment.
Compress a WAV into an M4A file in the browser. Export relies on MediaRecorder, so availability depends on which browser you use.
Shrink a heavy WAV into a compact AAC using the browser MediaRecorder. Support varies: if the codec is missing, the page says so instead of failing quietly.
Repack a WAV into an Opus-in-OGG file for websites and game prototypes. Export goes through MediaRecorder, so not every browser offers it.
Compress WAV into FLAC with no quality loss right in your browser: the file roughly halves while sample rate and bit depth stay exact. Nothing is uploaded.
Re-encode WAV into WebM/Opus online: pick a file, press Convert, download the result. The browser encodes it locally through MediaRecorder.
Extract the audio track from MP4, MOV, WebM or M4V video and save it as MP3 at the bitrate you choose. The video is never uploaded; your browser does the work.
Check whether your device makes any sound: the page generates a steady test tone with the Web Audio API, no software and no microphone needed.
A phone voice recorder writes M4A, a sound card and editing software hand you WAV, and almost every upload form asks for MP3. This hub collects every audio converter on the site so you do not have to hunt through the catalogue for the right format pair.
WAV is uncompressed: a minute of recording takes around ten megabytes, so a lecture or an interview stops fitting into an email attachment very quickly. MP3 shrinks that roughly tenfold and, for speech, the difference is not audible. For music, where losses show more, AAC and OGG do better at the same size, and FLAC compresses with no loss at all, to about half.
M4A to MP3 is the single most common request here. The format your iPhone and your messenger produce is rejected by older car stereos, by some content systems and by nearly every speech transcription service. Converting solves that in one step without recompressing the track twice.
Extracting audio from video deserves its own mention: a podcast cut from a call recording, or a music track from a clip, without opening an editor. Processing happens in the browser and nothing is uploaded.