Free AAC to M4A Converter: No Sign-up, Files Never Uploaded
This free AAC to M4A converter runs entirely on your device. You do not need an account or a login, and your files are never uploaded, so they never leave your browser.
The sound is decoded to raw samples and encoded again as M4A, so the length stays the same and only the packaging changes.
This pair runs on code that is already in the page, so there is no extra engine to download.
- Free
- No sign-up
- Never uploaded
- No watermark
Your files are converted on your device and never uploaded.
How to convert
- Add your AAC files by dragging them onto the converter or by using the file picker.
- Check that M4A is the selected target format; it is already chosen on this page.
- Open the options if you want to change bitrate, sample rate and channels, or keep the defaults.
- Press Convert and watch the progress shown for each file.
- Download each result, or take them all together as one ZIP when you converted several files.
Features
- Reads .aac and writes .m4a.
- Free, with no watermark added to the result.
- No sign-up and no login.
- Your files are never uploaded and never leave your device.
- Batch conversion with a ZIP download for several results.
- The input is recognised by its content, not only by its file name.
Supported formats
About the formats
About AAC
Advanced Audio Coding: the successor to MP3 with better quality at the same bitrate.
This is the raw AAC stream; the same audio inside an MP4 container is M4A.
About M4A
Audio in an MP4 container, usually AAC and sometimes Apple Lossless.
The default audio format of iTunes and Apple Music downloads.
AAC vs M4A
AAC does not support transparency, and M4A does not.
AAC files use the .aac extension and M4A files use .m4a, so the converted file gets a new name with the new extension.
Privacy: how it works
- Your AAC 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.
- 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.
Tips
- Keep your original recording. Encoding a lossy file again loses a little more quality each time.
- Choose a higher bitrate for music and a lower one for speech, where small files matter more than fine detail.
- Converting a lossy file to a lossless one only changes the container; it cannot bring back detail that is already gone.
- Convert one file first and listen before you start a long batch.
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 AAC 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.
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 AAC files one at a time if a big batch struggles.
What is the difference between AAC and M4A?
AAC does not support transparency, and M4A does not. AAC files use the .aac extension and M4A files use .m4a, so the converted file gets a new name with the new extension.
Can I convert many AAC files at once?
Yes. Add as many files as your device can handle. Each one is converted on its own and you can download them one by one or as a single ZIP.
Will anything be lost when I convert AAC to M4A?
The converter keeps the content of the file. Check the result once, since small differences in metadata or colour handling can happen between formats.
Can I convert M4A back to AAC?
Yes. Open the M4A to AAC page and use the same steps. Converting back does not undo any loss from the first conversion.