What is the difference between M4A, AAC and MP4?

AAC is the codec. M4A is an MP4 container that holds only audio; Apple chose the .m4a extension so players know not to expect video. An .m4r ringtone is the same file again under yet another name.

How do I turn an MP3 into an iPhone ringtone?

Convert it here, rename the result from .m4a to .m4r, then drag it onto your iPhone in Finder (macOS) or iTunes (Windows). Apple limits ringtones to 40 seconds, so trim the MP3 first if it is longer.

Is M4A better quality than MP3?

AAC is a more efficient codec, so a 192 kbps M4A generally sounds at least as good as a 192 kbps MP3. Converting cannot add back what the MP3 encoder removed, though.

Which bitrate should I use?

192 kbps, the default, is a safe match for most MP3s. Choose 256 kbps to match the iTunes Store, or 128 kbps for spoken word.

Will the M4A play on Android and Windows?

Yes. AAC has been supported on Android since the first release and on Windows since Windows 7, as well as in every browser.

Does it keep the cover art?

Yes. ID3 title, artist, album and artwork are rewritten as MP4 metadata, which the Music app, iTunes and Finder all display.

MP3 to M4A Converter — AAC for Apple Devices, Free

Convert MP3 to M4A

Convert MP3, WAV, FLAC or OGG to M4A, the AAC format Apple devices prefer for ringtones, Music libraries and iMovie projects. Converted in your browser.

No upload — runs in your browser

Batch convert & ZIP download

Free, no sign-up

Drop MP3, WAV, FLAC, OGG files here

Choose files

Free: up to 5 files per batch · Files never leave your device · Paste from the clipboard works too

Private by design

Your files are processed by your own device using WebAssembly and your browser's built-in codecs. Nothing is uploaded, logged or stored.

Fast & offline-ready

No queue, no waiting for a server. Once the page has loaded it even works without a connection.

Works everywhere

Chrome, Edge, Firefox and Safari on Windows, macOS, Linux, Android and iOS. No app to install.

M4A, AAC, MP4: one family, three names

When Apple launched the iTunes Store in 2003 it picked AAC over MP3 and gave audio-only MP4 files their own extension, .m4a. Two decades on, AAC is the default audio codec of iPhones, YouTube, most streaming services and every video camera. Tinyvert decodes your MP3 with the browser's decoder, then encodes AAC using the browser's own encoder where it has one and a WebAssembly encoder where it does not. Sample rate and channels are preserved, and ID3 tags become MP4 metadata.

Why people convert MP3 to M4A

Goal	Why M4A helps
Custom iPhone ringtone	Ringtones must be AAC; rename the output to `.m4r`
Tidy Apple Music library	Matches the format of purchased and ripped tracks
iMovie, Final Cut, Logic	AAC imports cleanly and keeps artwork
Smaller file at equal quality	AAC packs more into each kilobit than MP3
Uniform format across devices	One codec for iPhone, iPad, Mac, Android and web

Making a ringtone, start to finish

Convert the MP3 here at 192 or 256 kbps.
Rename song.m4a to song.m4r. The content is unchanged; only the extension tells iOS it is a ringtone.
Plug the iPhone in, open Finder or iTunes, and drag the file onto the device.
Choose it in Settings, Sounds & Haptics, Ringtone.

Apple caps ringtones at 40 seconds and alert tones at 30, so cut the track to length in any editor before converting. Tinyvert does not trim audio.

Choosing a bitrate

Because both formats are lossy, the usual advice applies: never pick a bitrate below the source. For a 128 kbps MP3, 128 or 192 kbps AAC is right; for a 320 kbps MP3, 256 kbps captures everything that is audibly left. Spoken word is happy at 96 kbps. If you still have the original CD rip or WAV, convert from that with the Audio Converter instead: one lossy generation beats two.

The other direction, and neighbours

M4A to MP3 reverses the process for players that only know MP3. Those with WAV recordings heading for Apple devices can go straight through WAV to MP3 if MP3 is acceptable, or use this tool, which accepts WAV too.

How to convert mp3 to m4a — step by step

Drop MP3 files (WAV, FLAC and OGG are accepted too) into the drop zone, or click "Choose files".
Pick a bitrate. 192 kbps is the default; 256 kbps matches Apple's own store encodes.
Conversion starts automatically. Each row shows its progress and then the size difference.
Download the M4A files, or on an iPhone tap Share to send one directly to GarageBand or Files.

Frequently asked questions

What is the difference between M4A, AAC and MP4?: AAC is the codec. M4A is an MP4 container that holds only audio; Apple chose the .m4a extension so players know not to expect video. An .m4r ringtone is the same file again under yet another name.
How do I turn an MP3 into an iPhone ringtone?: Convert it here, rename the result from .m4a to .m4r, then drag it onto your iPhone in Finder (macOS) or iTunes (Windows). Apple limits ringtones to 40 seconds, so trim the MP3 first if it is longer.
Is M4A better quality than MP3?: AAC is a more efficient codec, so a 192 kbps M4A generally sounds at least as good as a 192 kbps MP3. Converting cannot add back what the MP3 encoder removed, though.
Which bitrate should I use?: 192 kbps, the default, is a safe match for most MP3s. Choose 256 kbps to match the iTunes Store, or 128 kbps for spoken word.
Will the M4A play on Android and Windows?: Yes. AAC has been supported on Android since the first release and on Windows since Windows 7, as well as in every browser.
Does it keep the cover art?: Yes. ID3 title, artist, album and artwork are rewritten as MP4 metadata, which the Music app, iTunes and Finder all display.