Audio Converter

How it works

1. Choose one or more audio files, or drop them on the page.
2. Pick the output format and its quality settings.
3. Click Convert and wait for the progress bar to finish.
4. Download each file, or all of them as a ZIP.

What you can convert

Open MP3, WAV, M4A, AAC, FLAC, OGG (Vorbis or Opus), Opus, WebM, AIFF, WMA, AMR and CAF files, or the sound track of an MP4, MOV or MKV video. Write MP3, WAV, FLAC, M4A, AAC, OGG, Opus, WebM, AIFF, WMA or AMR.

Browsers decode most of these natively. For formats they cannot read, such as WMA, AMR and old Apple CAF files, a small decoder loads the first time you need it. Nothing is uploaded either way: both the decoding and the encoding run on your device.

Choosing the settings

Open Output settings to change quality. The summary row always shows what you will get, for example MP3, 192 kbps, original sample rate, stereo, together with an estimated file size.

• Bitrate: higher is larger and closer to the source. 128 kbps is fine for speech, 192 kbps is a good default for music, 320 kbps is the MP3 maximum. Leave it on Automatic when unsure.
• Sample rate and channels: keep Original unless a device needs something else. Mono halves the size of speech recordings. Some formats limit the choices (AMR is always 8 kHz mono, MP3 stops at 48 kHz) and the page tells you when it adjusted a value.
• WAV and AIFF: pick 16-bit for compatibility or 24-bit and 32-bit float for editing. FLAC offers 16 or 24-bit.
• Tags and artwork: keep them, or remove them for a clean file.
• Your last choice is remembered on this device for next time.

Lossy and lossless: what to expect

Converting from a lossy format (MP3, M4A, OGG, WMA) to another lossy format re-encodes the audio and costs a little quality. Converting lossy to WAV or FLAC does not restore detail that was already discarded; it only changes the container. Converting from WAV or FLAC to a lossy format is the normal way to make small files.

When the target container can hold the audio as it is (for example M4A to M4A with Automatic quality), the packets are copied without decoding. That is instant and keeps the quality exactly.

Batch conversion and ZIP

Add as many files as you like. They are converted one after another with the same settings, each with its own progress, and a file that fails does not stop the others. Finished files can be renamed, played, downloaded one by one, or downloaded together as a single ZIP.

Limits worth knowing

Very long files use a lot of memory when a format needs the whole recording in memory (WMA and AMR output, and formats decoded by the fallback decoder). On a phone, split very long recordings first. If a device is short of memory the page says so before it starts, and you can still try. WAV files above 4 GB switch to the RF64 variant automatically; AIFF cannot go above 4 GB.

Questions