MP3 to M4A converter
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Turn MP3 songs and recordings into AAC-encoded M4A files, ready for Apple devices, without uploading them.
M4A is an audio file with AAC sound, the format Apple Music and iPhones use natively and that some apps, voice tools and course platforms ask for by name. This converter decodes your MP3 and encodes it again as AAC-LC in an .m4a file, using the audio encoder built into your browser. Typical jobs: cutting a 30-second piece of a song for an iPhone ringtone, bringing an old MP3 collection in line with an Apple Music library, or meeting an upload form that accepts only M4A. WAV, FLAC and OGG files work too when your browser can read them.
How to convert MP3 to M4A
- Add the MP3 files (WAV, FLAC or OGG are accepted as well).
- Choose the AAC bitrate: 192 kbps is the default and matches a typical MP3; 128 kbps is enough for speech and ringtones, 256 or 320 kbps for a high-bitrate MP3. For a ringtone, set a start and end time no more than 40 seconds apart.
- Convert and download each M4A, or all of them in one ZIP.
What happens to quality, size and metadata
MP3 and AAC are both lossy, so this is a second round of compression: the M4A can never sound better than the MP3 it came from. At the same bitrate the two sound about the same to most listeners. AAC is the more efficient codec, so AAC at 128 kbps is roughly comparable to MP3 at 160–192 kbps; choosing a bitrate far above the source only makes the file bigger. The audio keeps its sample rate and stereo channels. Tags such as title, artist and album art are not carried over, so add them in Music or your player afterwards. If your browser has no AAC encoder, the page tells you before you start.
MP3 vs M4A
| Full name | MP3 | M4A |
|---|---|---|
| Full name | MPEG-1 Audio Layer III | MPEG-4 Audio |
| Introduced | 1993 | 2003 |
| Defined by | MPEG · ISO/IEC 11172-3 | MPEG · ISO/IEC 14496-14 + 14496-3 (AAC) |
| Compression | Lossy | Lossy or lossless |
| Chrome / Edge | Yes | Yes |
| Safari | Yes | Yes |
| Firefox | Yes | Partly |
| Windows | Yes | Yes |
| iPhone / iPad | Yes | Yes |
| Android | Yes | Yes |
| Typical use | Music, podcasts, voice recordings and any audio that has to play on every device. | iPhone Voice Memos, music from Apple apps, and audio extracted from MP4 video. |
MP3 MP3 is the lossy audio format standardised by MPEG in ISO/IEC 11172-3 (1993). Its patents have expired, and practically every player, car stereo, phone and editing app plays it. At 192 kbps most listeners cannot tell it from the original on typical speakers or headphones.
M4A M4A is an MP4 file that contains only sound, nearly always AAC (sometimes Apple Lossless). AAC sounds better than MP3 at the same bitrate. Apple devices use it for voice memos and music, but some older players, car stereos and websites accept only MP3.
Sources for this table
- www.iso.org/standard/22412.html
- www.rfc-editor.org/rfc/rfc3003
- caniuse.com/mp3
- developer.android.com/media/platform/supported-formats
- www.rfc-editor.org/rfc/rfc4337
- www.iso.org/standard/76383.html
- caniuse.com/aac
Browser support data: caniuse.com, CC BY 4.0.
Without this site
Mac: in the Music app open Music › Settings › Files › Import Settings and pick AAC Encoder, then select the song and choose File › Convert › Create AAC Version; the M4A appears next to the MP3 in your library. Windows: iTunes for Windows has the same option under Edit › Preferences › General › Import Settings and File › Convert. iPhone: GarageBand can turn a song in the Files app into a ringtone. Android has no built-in MP3 to M4A converter.
Troubleshooting
- “This browser can’t encode AAC”. Some browsers ship without an AAC encoder. Open the page in a current Chrome, Edge or Safari.
- Making an iPhone ringtone. Trim to 40 seconds or less, then rename the .m4a to .m4r and add it to the iPhone through Finder (Mac) or iTunes (Windows).
- Song titles and covers are gone. Tags aren’t copied. Re-enter them with Get Info in Music or your player.
- You want the opposite. For M4A files that must play on older players, use M4A to MP3.
Questions and answers
How do I convert MP3 to M4A for free?
Add the MP3 on this page, keep 192 kbps and press Convert. The browser encodes the sound as AAC and saves an .m4a file in Downloads within seconds for a normal song. There is no account, no watermark and no file limit, and the audio is never uploaded to a server.
Is M4A better quality than MP3?
The AAC codec in M4A sounds better than MP3 at the same low bitrate: AAC at 128 kbps is close to MP3 at 160–192 kbps. But converting an existing MP3 cannot add back detail it already lost. Expect the M4A to sound the same as the MP3, not better; the benefit is compatibility.
How do I make an MP3 into an iPhone ringtone?
Convert the MP3 here with a start and end time that keep 40 seconds or less, then rename the downloaded file from .m4a to .m4r. On a Mac, connect the iPhone and drag the .m4r onto it in Finder; on Windows, use iTunes. It then appears in Settings › Sounds & Haptics › Ringtone.
What bitrate should I use for MP3 to M4A?
Match or slightly undercut the MP3. For a 320 kbps MP3, 256 kbps AAC keeps all the detail that is left. For a 128 kbps MP3, 128 kbps AAC is plenty. 192 kbps is a safe default for music, and speech or ringtones need no more than 128 kbps.