Convert MP3 files into the M4A format, which fits especially well into Apple apps and iPhones. Conversion runs right in your browser, so your files are not uploaded by default.
In “Local” mode your file never leaves your device. No uploads, no server – ideal for sensitive recordings.
Pick “Local” for full privacy or “Server” for very large files and every format.
No sign-up, no queue, no watermark. Choose a file, convert, download.
No. Both MP3 and M4A are lossy, and converting between two lossy formats can even shed a tiny bit more quality. A genuine improvement isn't possible.
Usually for compatibility: M4A slots neatly into iTunes, Apple Music and the iOS library, where M4A is often preferred.
No, everything runs locally in your browser by default. For very large files there is an optional server mode.
The size stays in a similar range since both formats compress well. Depending on the bitrate, the M4A may end up slightly smaller or larger.