MP3 to M4A Converter
MP3 plays almost everywhere, so converting it to M4A is usually about a specific destination: an app or form that asks for .m4a, an Apple-centered library, or a smaller AAC copy. Here is how to do it without making the audio worse than it needs to be.
Audio Converter
or drop MP3, WAV, M4A … files here ·
Max 95 MB per file· Up to 20 files· Deleted after 30 minutes
Files are processed on our servers and deleted after 30 minutes.
Constant bitrate (CBR) gives a predictable size and works on every player. Variable bitrate (VBR) spends bits where the music needs them and is usually smaller at the same quality.
Keep the source rate unless a device asks for one. 44.1 kHz is CD standard, 48 kHz is video standard, 8 kHz is used by phone systems and AMR.
Mono halves the size of lossless files and is fine for voice recordings.
16-bit is CD quality. 24-bit keeps headroom for editing and mastering; converting a 16-bit source up does not add detail.
Optional. Seconds (e.g. 75) or minutes:seconds (1:15). Leave empty to start at the beginning.
Optional. Same format as the start time. Leave empty to keep everything up to the end.
How to use this tool
- 1
Upload MP3 files
Add up to 20 MP3s, each up to 95 MB. Songs, podcasts, lectures and voice recordings all work.
- 2
Set the AAC bitrate
Convert to is already M4A and Bitrate is 192 kbps. Pick a value at or a step below your MP3's bitrate; a 320 kbps song keeps its sound at 256 kbps AAC.
- 3
Convert to M4A
Press Convert to M4A and save the files, separately or in one ZIP. Every upload is deleted after 30 minutes.
To convert MP3 to M4A, upload the files and press Convert to M4A at 192 kbps or at your MP3's own bitrate. The AAC audio sounds the same as the source; it cannot sound better, because the MP3 already set the ceiling.
Reasons to convert MP3 to M4A
M4A is an MPEG-4 file holding AAC audio. AAC was standardized in 1997 as part of MPEG-2 and carried into MPEG-4, and the MP4 container itself was based on Apple's QuickTime format. Apple made the .m4a extension familiar when the iTunes Store opened in 2003 selling AAC tracks, and it remains the native audio type of the Music app and Voice Memos.
So most MP3 to M4A conversions answer a request. A course platform or app may accept .m4a recordings only; a family library may be kept entirely in Apple's format; a podcast editor might want a smaller upload. AAC also handles low bitrates better than MP3, which means an M4A at a lower bitrate can match a bigger MP3. For raw AAC streams without the MP4 wrapper, MP3 to AAC writes .aac files instead.
MP3 to M4A converter: what you gain and what you give up
| MP3 | M4A (AAC) | M4A (Apple Lossless) | |
|---|---|---|---|
| Plays in Apple Music, iPhone and iPad | yes | yes | yes |
| Same perceived quality at a lower bitrate | no | yes | Lossless |
| Reads on older car stereos and MP3 players | yes | Varies | no |
| Audio type behind iPhone .m4r ringtones | no | yes | no |
| Worth making from an MP3 source | Source | yes | no |
Converting helps when
- A form, app or teacher asks for .m4a
- You want smaller files at the same perceived quality
- Your library is managed in Apple's Music app
Keep the MP3 when
- The destination is a car stereo or older player
- You hoped to improve the sound
- You might need to convert again later; each lossy pass adds error
Choosing the M4A bitrate from your MP3's bitrate
Start from what the MP3 already is. A 320 kbps song converts well to 256 kbps AAC, the rate Apple has sold iTunes Plus music at since 2007. A 192 kbps file keeps its character at 160 or 192 kbps, and a 128 kbps lecture or podcast can go to 96 kbps with Mono under Channels. Never choose more than the MP3's own bitrate: it only adds size. Going back the other way is a job for M4A to MP3.
MP3 and M4A format facts
MP3
MP3 audio
MP3 (MPEG-1 Audio Layer III) is a lossy audio format developed largely at the Fraunhofer Institute and standardised by MPEG in 1993. It removes sounds the ear is unlikely to notice, shrinking music to about a tenth of CD size at 128–320 kbps. All patents have expired, and every phone, car stereo, browser and media player supports it. Quality loss is audible at low bitrates and accumulates with re-encoding.
- Compression
- Lossy
- Transparency
- –
- Animation
- –
- Introduced
- 1993 · Fraunhofer IIS / MPEG
M4A
MPEG-4 audio (M4A)
M4A is an audio-only MPEG-4 file, popularised by Apple's iTunes. It usually contains lossy AAC audio, but it can also hold lossless ALAC. AAC in M4A generally sounds better than MP3 at the same bitrate, and the format is used for iPhone voice memos, Apple Music downloads and many podcasts. Most modern devices play M4A, but some older players, car stereos and web tools only accept MP3.
- Compression
- Lossy or lossless
- Transparency
- –
- Animation
- –
- Introduced
- Apple / MPEG
MP3 is changed to M4A when a destination names it: an upload form or app that accepts only .m4a, a library kept consistent with iTunes purchases, or a lower-bitrate AAC copy that sounds as good as the larger MP3.
MP3 to M4A: answers
Does an M4A made from an MP3 sound better than the original?
No. The MP3 encoder already removed some detail, and the AAC encoder works from that reduced signal, so the best result is a copy that sounds the same. The benefit of M4A here is compatibility with a particular app or a smaller file, never a quality gain.
Why is my M4A about the same size as the MP3?
File size follows bitrate: 192 kbps is roughly 1.4 MB per minute in either format. To save space, choose a lower Bitrate than the MP3 used, for example 128 kbps AAC from a 192 kbps MP3, and let AAC's efficiency carry the quality.
Can I join several MP3 chapters into one M4A?
No, each uploaded MP3 becomes its own M4A file; this tool converts but does not merge. Join the chapters in an audio editor first, then convert the single long MP3 here.
Is M4A the right choice for an iPhone ringtone?
A ringtone uses the same AAC audio, but iPhone expects the .m4r extension and a short clip. Use MP3 to M4R, which writes the ringtone format directly, and trim the song with Start at and End at.
Do lyrics, artwork and track numbers come across?
With Keep tags and cover art on, title, artist, album, track number and the embedded cover are copied from the MP3's ID3 tags into the MP4 tag fields that Apple apps read. Rarely used ID3 frames without an MP4 equivalent can be dropped.