Free Audio Converter: No Sign-up, No Upload, No Watermark
This audio converter is free, needs no sign-up or login, and does not upload your files anywhere. Songs, voice memos, recordings and lectures are decoded and re-encoded inside your browser, so they never leave your device, and nothing is added to the result. Choose the format your player, phone or editing tool expects and download it.
It handles the common formats and the awkward ones: MP3, WAV, OGG, Opus, AAC, M4A, FLAC, ALAC, WebM Audio, AIFF, AC3 and AMR can all be created, and WMA, CAF, AU, MKA and MP2 can be opened and converted to something more usable. You can also take the sound track out of a video file and save it as audio.
Conversion runs on your own processor. Many pairs use the audio codecs already built into your browser and start at once. A few need a larger conversion engine that is downloaded one time, and the page tells you before it does.
- Free
- No sign-up
- Never uploaded
- No watermark
Your files are converted on your device and never uploaded.
How to convert
- Drag audio or video files onto the page, or pick them with the file chooser.
- Select the target format, for example MP3 for compatibility or FLAC for lossless storage.
- Review any options shown for that format, such as the bitrate of a lossy file.
- Press Convert and let your device process the files.
- Download one file straight away, or download a batch as a single ZIP.
- Play the result before you delete the original, especially for long recordings.
Features
- Creates MP3, WAV, OGG, Opus, AAC, M4A, M4R, FLAC, ALAC, WebM Audio, AIFF, AC3 and AMR.
- Reads WMA, CAF, AU, MKA and MP2 files and converts them to common formats.
- Extracts the audio track from video files.
- Makes iPhone ringtones in M4R, which iPhone limits to 40 seconds.
- Converts several files at once and offers a ZIP download.
- Lossless targets (WAV, FLAC, ALAC, AIFF) keep everything the source holds.
- Uses built-in browser codecs where possible and a one-time engine only where needed.
- Adds no watermark and no jingle to your audio.
Supported formats
| Format | Read | Write | Notes |
|---|---|---|---|
| MP3.mp3 | Yes | Yes | Lossy audio format that plays on practically every device. |
| WAV.wav | Yes | Yes | Usually uncompressed PCM audio, so files are large. |
| OGG.ogg | Yes | Yes | Container from the Xiph.Org Foundation, usually holding Vorbis or Opus audio. |
| Opus.opus | Yes | Yes | Open, royalty-free codec standardised by the IETF in 2012 (RFC 6716). |
| AAC.aac | Yes | Yes | Advanced Audio Coding: the successor to MP3 with better quality at the same bitrate. |
| M4A.m4a | Yes | Yes | Audio in an MP4 container, usually AAC and sometimes Apple Lossless. |
| M4R.m4r | Yes | Yes | iPhone ringtone: an M4A file with the .m4r extension. |
| FLAC.flac | Yes | Yes | Free Lossless Audio Codec: compresses audio without discarding anything. |
| ALAC.m4a | Yes | Yes | Apple Lossless: lossless compression stored in an M4A file. |
| WebM Audio.weba | Yes | Yes | Audio-only WebM file, normally holding Opus or Vorbis. |
| AIFF.aiff | Yes | Yes | Apple’s uncompressed PCM audio format, introduced in 1988. |
| WMA.wma | Yes | No | WMA encoding is not offered; open the file and convert it to MP3, WAV or another format. |
| AMR.amr | Yes | Yes | Adaptive Multi-Rate: a speech codec standardised by 3GPP for mobile phones. |
| AC3.ac3 | Yes | Yes | Dolby Digital: lossy surround-sound audio, up to 5.1 channels. |
| CAF.caf | Yes | No | CAF is read only here; convert it to WAV, FLAC or MP3. |
| AU.au | Yes | No | AU is a legacy format that is read only here; convert it to WAV or MP3. |
| MKA.mka | Yes | No | MKA is read only here; convert it to MP3, FLAC or WAV. |
| MP2.mp2 | Yes | No | MP2 is read only here; convert it to MP3 or WAV. |
| WebM.webm | Yes | Yes | Open, royalty-free format from Google, usually VP9 or AV1 video with Opus audio. |
About the formats
Lossy and lossless audio
MP3, AAC, OGG, Opus, M4R, AC3, AMR and WebM Audio are lossy: they discard sound that is hard to hear in order to make small files. WAV, AIFF, FLAC and ALAC are lossless, so nothing is discarded. WAV and AIFF are usually uncompressed and large, while FLAC typically shrinks audio to roughly half its uncompressed size.
Converting lossy to lossless does not restore what was lost, it only makes a bigger file. Converting lossy to another lossy format loses a little more each time, so convert from the highest-quality source you still have.
MP3 vs AAC vs Opus
MP3 plays on practically every device, which is why it remains the safe choice for sharing. AAC is the successor to MP3 and gives better quality at the same bitrate, and the same audio inside an MP4 container is M4A. Opus is an open codec standardised by the IETF and is very good at low bitrates, so it suits voice and streaming, but some older players cannot open it.
WAV, AIFF, FLAC and ALAC
WAV was created by Microsoft and IBM and is the usual choice for editing. AIFF is the Apple equivalent, common in music production on a Mac. FLAC is open and widely supported on Android and in hi-fi software. ALAC is Apple Lossless, stored in an M4A file, and plays across Apple devices. All four keep full quality.
M4A, M4R and AAC
An M4A file is audio in an MP4 container, usually AAC and sometimes Apple Lossless. An M4R file is an M4A with a different extension, used for iPhone ringtones, which are limited to 40 seconds. A bare AAC file is the raw stream without the container, which some players handle less well than M4A.
Older and read-only formats
WMA is a lossy Microsoft format from the late 1990s, and AU came from Sun Microsystems. CAF is a container used mostly in Apple software, MKA is the audio-only sibling of MKV, and MP2 is the predecessor of MP3. All five can be opened and converted, but not created. AMR is a speech codec for mobile phones, so music sounds poor in it.
When an engine download is needed
Pairs that involve WMA, AMR, AC3, CAF, AU, ALAC or MP2 use a WebAssembly engine of about 31 MB, as can AAC, M4A, Opus or OGG output on a browser without those encoders built in. It downloads once and is kept by your browser. Only the engine is fetched, never your audio.
Privacy: how it works
- Your audio files stay on your device. The page reads each file with the browser's file API, converts it with code running in the tab, and hands the result back as a download. No upload happens, so there is no copy of your file on our servers to protect, delete or leak.
- There is nothing to sign up for and no login. The converter does not ask for an email address, and it does not need to know who you are to do its job.
- Some conversions use a WebAssembly engine that your browser downloads once, the first time you need it. Only the engine is fetched, never your file, and the page shows the approximate size before it starts. Your browser caches it, so later conversions skip the download.
- You can check the claim yourself: open your browser developer tools, watch the Network tab while a file converts, and you will see no request that carries your file.
- Voice notes, interviews and meeting recordings can be private. Because decoding and encoding happen on your device, the sound is never copied to a server, which makes this a reasonable choice for recordings you would rather not share.
Tips
- For music you want to play anywhere, choose MP3 or M4A at a reasonable bitrate.
- For an archive of music you care about, choose FLAC and keep the lossless copy.
- For editing in a recording or video tool, WAV is the safest input.
- Voice recordings can use a lower bitrate than music without sounding worse.
- To make an iPhone ringtone, convert to M4R and keep the clip under 40 seconds.
- To get the sound from a video, add the video file and pick an audio format.
- Do not convert an MP3 to FLAC expecting better sound: the lost detail does not come back.
- Convert long files one at a time on a phone to avoid running out of memory.
Frequently asked questions
Is it really free?
Yes. There is no price, no trial, no credit card and no watermark added to your results. Ulkaa Tool does the conversion with your own device, so there is no server bill to pass on to you.
Are my files uploaded?
No. Your audio files are read and converted inside your browser and are never sent to Ulkaa or to anyone else. The result is created on your device and you save it from there. Some conversions load a small conversion engine the first time you use them. That download is the only network traffic, it contains no file of yours, and your browser keeps it for next time.
Do I need an account?
No. There is no sign-up and no login. Open the page, add your files and convert. An Ulkaa account is not needed for anything on this tool.
Is there a file size limit?
No limit is set by us. The real limit is your device: the conversion uses your own memory and processor, so very large files can be slow or fail on a weak phone or an older computer. Close other heavy tabs and convert audio files one at a time if a big batch struggles.