Convert audio formats
Convert between MP3, WAV, M4A (AAC), OGG (Opus) and FLAC, plus AAC (ADTS), OPUS, AIFF and M4R (iPhone ringtones), or pull just the audio out of MP4, MOV and WebM videos. Bitrate, mono downmix, sample rate and the bit depth of WAV / AIFF can be set.
Settings
How to use
- 1
Add audio or video
MP3, WAV, M4A, FLAC and other audio files, or video files such as MP4 and MOV to extract the audio from.
- 2
Choose format and bitrate
Pick MP3, M4A, WAV, AAC, OGG, OPUS, FLAC or AIFF. You can also downmix to mono or change the sample rate.
- 3
Convert and save
Press Run. Multiple files are processed in turn and can be saved together as a ZIP.
Choosing a format
MP3 for maximum playback compatibility, M4A (AAC) for Apple devices and phones, OGG (Opus) for small web or voice-quality files. For editing intermediates or CD quality, choose WAV or FLAC (lossless).
Converting between lossy formats (MP3, M4A, OGG) accumulates loss. If you still have a WAV or FLAC original, convert from that. Speech recordings are fine at 96–128 kbps; music wants 192–256 kbps.
Frequently asked questions
Can I extract just the audio from a video?
Yes. Drop an MP4, MOV, WebM or MKV and only the audio track is written in the chosen format. The video is skipped, so even long videos finish quickly. Recordings of X (Twitter) Spaces and X videos saved with the same author's X Space Downloader / X Video Downloader can be loaded as they are.
Is there a length or size limit?
None from the site. Conversion streams the file rather than loading it all into memory, so recordings of several hours work.
Are there devices that cannot convert to MP3?
If the browser has no MP3 encoder, LAME is loaded automatically as WebAssembly, so MP3 works in every major browser. M4A (AAC) and OGG (Opus) depend on the browser's built-in encoders and are disabled on devices that lack them.
Which bitrate should I use?
96–128 kbps is enough for speech and lectures. Use 192 kbps or more for music. WAV, AIFF and FLAC are lossless and have no bitrate setting; for WAV and AIFF you choose the bit depth instead (16 / 24-bit, plus 32-bit float for WAV).
Help us improve the service
If a conversion fails, sending us the circumstances helps us track down the cause. Knowing which devices and formats fail most often, and how long processing takes, lets us revise the supported formats and fix the bugs behind them. If you don't mind, leaving this on is a real help.
What is sent
- The tool you used and the settings you chose (output format, quality, etc.)
- Your device specs (GPU, memory, core count)
- The input format with a rough size
- How many files succeeded or failed and how long it took
- The error type and details when something fails
What is never sent
- The files themselves and file names
- Text, subtitles or prompts you add to a video
- The text to be read aloud, voice descriptions, the pronunciation dictionary and saved voices
- The text in PDFs, the text you rewrote or redacted, passwords, font names and the page ranges you enter
- IP addresses
The data goes only to this site's own server, never to a third-party service.
Details sent by specific tools (counts, times, kinds and yes/no only)
In addition to “What is sent”, text to speech and the PDF tools send the following details.
- Text to speech
- The approximate number of characters and sentences, how many parts the text was generated in, and how long the AI model took to load.
- PDF tools (all)
- The page count range, whether editing is restricted, whether a permissions password was entered, and whether the PDF is signed or encrypted.
- PDF text editing and redaction
- The numbers of rewrites, deletions, white-outs and redactions, the number of rewritten characters by source (original font or fallback font, the latter as a range) and the fallback typeface, the kinds of reasons why lines cannot be edited, and the number of pages turned into images by redaction and the reasons.
- PDF page operations and conversion between images and PDF
- The numbers of inputs and outputs, of pages rotated, deleted, duplicated or moved, of images inserted as they are, converted, in HEIC format or with corrected orientation, and of pages rendered at a lower resolution (all as ranges), whether the original was updated in place or a new document was created, and whether the original protection was reapplied, form fields were written into the page and bookmarks were added back.
- PDF compression
- The numbers of inputs and outputs, of images downsized, not downsized and black-and-white, of downsized images whose transparency was also downsized, that stayed lossless or that were converted from CMYK to RGB, and how many times the file was compressed (all as ranges), the kinds of reasons images were not downsized, whether the target size was met and the kind of reason it was not met, the range of how much smaller the file got, whether the original protection was reapplied, and whether the original PDF was returned unchanged.
- PDF cropping and page numbers
- The numbers of inputs and outputs and of pages cropped, numbered or with their margins reduced (all as ranges), how the margins were set, how the pages to crop or number were chosen, the number format and position, the range of the starting number, that the original was updated in place, and whether the original protection was reapplied.