Convert MP3 to M4A
Re-encode an MP3 as 192 kbps AAC in an .m4a file for apps and workflows that require M4A, such as iPhone ringtone prep. Free, up to 50 MB.
Re-encode an MP3 as 192 kbps AAC in an .m4a file for apps and workflows that require M4A, such as iPhone ringtone prep. Free, up to 50 MB.
An M4A file is an MP4 container carrying AAC audio. It's the format of iTunes Store purchases and a common choice in Apple apps, Android apps and web tools. To make one, this converter decodes your MP3 and encodes it again as AAC-LC at 192 kbps. The sample rate and channel layout of the MP3 are kept, and the file is written with fast-start, meaning its index sits at the beginning so playback can begin before a web download finishes.
One thing to know up front: M4A is not an upgrade over MP3. Every iPhone, Mac and modern media player already plays MP3. Convert only when an app, device or workflow specifically asks for M4A or AAC.
Both formats are lossy, so this is a second generation of compression. The AAC encoder receives the MP3's audio with its existing losses and applies its own. At 192 kbps the added loss is usually inaudible when the MP3 was good to begin with, but nothing improves: a low-bitrate MP3 keeps its muffled highs and warbly artifacts. Avoid converting the same track back and forth between lossy formats, and if you still have a lossless original, convert from that instead through the M4A converter.
| Your MP3 | MP3 per minute | M4A per minute | Result |
|---|---|---|---|
| 128 kbps | 0.96 MB | 1.44 MB | larger file, same sound quality at best |
| 192 kbps | 1.44 MB | 1.44 MB | about the same size |
| 320 kbps | 2.4 MB | 1.44 MB | smaller file, slight extra loss possible |
AAC is generally more efficient than MP3, meaning it tends to sound cleaner at the same bitrate when both are encoded from the same lossless master. That advantage only applies at the original encoding stage. Once audio has been through an MP3 encoder, a new AAC encode can't undo those decisions, so the M4A you get here is limited by the MP3 you started with. Voice recordings and spoken-word MP3s behave the same way; a mono MP3 simply becomes a mono M4A.
iPhone ringtones are AAC files with the .m4r extension, and they need to be 40 seconds or shorter. This site outputs .m4a and has no trimming, so the workflow has a few parts:
.m4a to .m4r.GarageBand on the iPhone can also turn an MP3 into a ringtone directly, if you'd rather stay on the phone.
Some e-learning platforms, voice-message tools and app projects accept AAC in M4A but not MP3. Converting saves you from finding a different upload route.
If the rest of your collection is AAC, converting the odd MP3 keeps file types uniform for tools that sort or process by format.
| MP3 | M4A | |
|---|---|---|
| Full name | MPEG-1/2 Audio Layer III | MPEG-4 Audio (AAC in an MP4 container) |
| Compression | Lossy | Lossy (AAC) |
| Developed by | Fraunhofer IIS / MPEG | MPEG / Apple |
| Introduced | 1993 | 2003 |
| File extension | .mp3 | .m4a |
| Typically used for | Music libraries, podcasts, everyday listening | Apple Music and iTunes libraries, iPhone voice memos, podcasts |
| Plays on | Virtually every phone, computer, browser, car stereo and media player | Apple devices, Android, Windows 10+, modern browsers |
| Our output | LAME MP3, 192 kbps CBR, stereo | AAC-LC 192 kbps in MP4, fast-start |
Not when you convert from an MP3. AAC can be more efficient than MP3 when both are encoded from a lossless source, but your MP3 has already lost detail. Re-encoding it to 192 kbps AAC adds a small, usually inaudible second loss and can't improve anything. Convert only if something specifically needs M4A.
Trim the part you want to 40 seconds or less in an audio editor, since this site has no trimming. Convert the clip to M4A here, rename the downloaded file from .m4a to .m4r, and sync it to your iPhone with Finder on a Mac or iTunes on Windows. GarageBand on iPhone is another option.
Our M4A output is always 192 kbps, about 1.44 MB per minute. A 192 kbps MP3 converts to a file of about the same size, a 128 kbps MP3 gets about 50 percent larger, and a 320 kbps MP3 gets smaller. The smaller file doesn't match the 320 kbps MP3's quality.
It's AAC-LC at 192 kbps inside an MP4 container, with the sample rate and channels of your MP3 kept and fast-start enabled for web playback. The .m4a extension is also used for Apple Lossless, but this converter doesn't create ALAC. A lossless container wouldn't bring back quality from an MP3 anyway.
Basic text tags such as title and artist often come through, but embedded cover art is dropped because the converter writes audio only. There's no tag editor on this site, so add artwork in your music app afterward. Your uploaded MP3 is deleted after conversion and the M4A within about an hour.
Need detailed information or want to set a different default format? Visit our specific converter pages: