One converter for every common audio format
Phones record in M4A, cameras save WAV, music stores sell MP3 or FLAC, and chat apps send Opus voice notes. Sooner or later one program refuses a file because it has the wrong format. This audio converter changes the format of one file or many at once. It understands MP3, WAV, AIFF, FLAC, AAC, M4A, M4R, OGG, OPUS, WMA and MMF, and it can also take the soundtrack from MP4, MOV, WebM and other video files.
The converter runs a full copy of FFmpeg, a well-known open-source media engine, directly in your browser tab. Files are read from your disk, converted in memory and handed back to you. They are not uploaded, so private recordings stay private and large files do not have to cross a slow connection.
Lossy or lossless: the one choice that matters most
Audio formats fall into two families. Lossless formats (WAV, AIFF, FLAC) store every sample exactly. Lossy formats (MP3, AAC, M4A, OGG, OPUS, WMA) remove sounds that are hard to hear in order to make files about ten times smaller.
- Going from lossless to lossy is normal: pick a bitrate that suits the material, for example 192 to 256 kbps for music or 64 to 96 kbps for speech.
- Going from lossy to lossless never restores the removed detail. It only makes the file bigger. Do it when an editor or a device insists on WAV or FLAC.
- Going from one lossy format to another adds a second round of loss. Use the same or a higher bitrate than the source to keep it inaudible.
Pick a converter by source format
Each format has its own page with advice about its target formats, typical problems and best settings:
- MP3 converter: the most common starting point, for example to make WAV for editing or M4R for an iPhone.
- WAV converter: shrink large recordings to MP3 or archive them as FLAC.
- FLAC converter: make lossless music playable on phones, cars and Apple devices.
- M4A converter: open iPhone voice memos and iTunes files anywhere.
- AAC converter and AIFF converter for raw AAC streams and Mac audio.
- OGG, OPUS, WMA, M4R, MMF and MIDI converters for the rest.
Settings you can change
| Setting | Applies to | Typical value |
|---|---|---|
| Bitrate | MP3, AAC, M4A, M4R, OPUS, WMA (OGG uses quality levels) | 192 kbps for music, 64 to 96 kbps for voice |
| Sample rate | all formats except OPUS (always 48 kHz) | keep the original (44.1 or 48 kHz) |
| Channels | all formats except MMF (always mono) | stereo for music, mono for speech |
| Bit depth | WAV, AIFF, FLAC | 16-bit, or 24-bit for studio work |
Settings apply to every file in the batch. Text tags such as title, artist and album are copied when the target format can hold them. Raw AAC, WAV and MMF files store little or no metadata, so tags may be lost there. Cover art is copied into MP3, M4A, M4R and FLAC files.
Beyond plain format changes
Some pages go further than a simple format change. The audio to MIDI pages turn a recorded melody into notes with a machine learning model that runs on your device. The audio to MP4 pages make a video from a song and a picture, ready for video sites. If you need to change the length or loudness instead of the format, try the audio editor or compress audio.