MP3 → M4A · Free · No signup

MP3 to M4A
Free online converter

Drop an MP3. Get an M4A, AAC audio inside an MP4 container. Plays natively in iTunes, Apple Music, and on every iPhone. No watermark, no email.

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Drop your .mp3 file

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Max 25 MB · .mp3 only

How it works

📂

Drop the MP3

Drag any MP3 into the box. Up to 25 MB anonymously, 60 MB after signup.

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ffmpeg re-encodes to AAC

128 kbps AAC inside an M4A container, with the faststart flag so it plays immediately when streamed. Finishes in 3-10 seconds.

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Download the M4A

Result has the original name with .m4a. Files are wiped from our servers within the hour.

Why convert MP3 to M4A

Apple ecosystem prefers M4A

iTunes, Apple Music, iCloud Music Library, GarageBand, they all handle M4A as the first-class format. MP3 works too, but M4A is what they speak natively.

AAC sounds slightly better than MP3 at the same bitrate

At 128 kbps the difference is small but real, especially in the high frequencies. If your source MP3 is already lossy, this re-encode does not make it worse.

M4A supports chapter markers and richer metadata

If you are making audiobooks, podcast preview files, or anything for the Apple ecosystem, M4A handles chapters cleanly. MP3 chapter support is patchy.

iPhone ringtones must be M4A

Custom iPhone ringtones use the M4R extension, same AAC-in-MP4 format as M4A. Convert and rename to .m4r for ringtone use.

No watermark, no upsell

Your audio re-encoded, nothing else.

When you would convert MP3 to M4A

Importing a music collection into Apple Music

M4A imports cleanly and integrates with iCloud Music Library. MP3s can occasionally have metadata issues during sync.

Making an iPhone ringtone

Convert MP3 → M4A, trim to under 40 seconds, rename to .m4r, drop into Finder while iPhone is connected.

Audiobook with chapter markers

M4A supports chapters; MP3 support is unreliable. For long audiobooks where listeners want to jump between chapters, M4A is the right format.

Voice memo cleanup for iCloud

If you have a folder of MP3 voice memos and want them in iCloud or Apple Voice Memos, M4A is more native and syncs more reliably.

GarageBand or Logic project

When importing reference audio into Apple's music software, M4A drops in smoother than MP3 in some workflows.

Tips for MP3 to M4A conversion

Re-encoding does add a tiny amount of loss

You are going from one lossy format to another. At 128 kbps AAC from a 128 kbps MP3, the loss is real but inaudible to almost everyone on almost everything. For critical use, find a lossless source.

For ringtones, trim before converting

iPhone ringtones cap at 40 seconds. Trim the MP3 in Audacity or QuickTime first, then convert.

AAC at 96 kbps usually beats MP3 at 128 kbps

Our converter outputs at 128 kbps for compatibility, but if you have full control you could go lower with AAC and still match MP3 quality. We do not offer the picker to keep the tool simple.

M4A vs MP4, same container, different convention

M4A files contain only audio. MP4 files can contain video, audio, or both. iTunes uses the .m4a extension to make the distinction obvious. Some players accept either extension.

Chapter markers are not added by us

We just re-encode the audio. To add chapter markers, use Apple Books for audiobooks or a dedicated tool like Chapter and Verse.

For DRM-protected MP3s, conversion will fail

DRM is extremely rare for MP3 in 2026, but if you somehow have one, it will not decode.

MP3 to M4A is bringing audio into the Apple ecosystem

MP3 plays everywhere, including in iTunes and Apple Music. So why convert? The reasons are narrow but real. iPhone ringtones require .m4r (which is just M4A renamed). The Apple Music app handles M4A metadata more cleanly than MP3 ID3 tags. Audiobook chapter markers only work in M4B (another M4A variant). And some Apple-ecosystem workflows (Sidecar, Continuity, AirDrop) feel more native with M4A.

What you actually gain in the conversion

Better tagging in Apple Music. iTunes-style metadata fields (sort artist, sort album, compilation flag) that MP3 ID3 handles awkwardly. Native Apple ecosystem feel: the file looks like a first-class Apple Music item, not an imported stranger. Album artwork tends to survive better in M4A than in MP3 when shared between Apple devices.

What you do not gain: audio quality

MP3 to AAC (the codec inside M4A) is a lossy-to-lossy re-encode. The AAC output cannot be better than the MP3 it came from. Going through two lossy codecs adds a small quality loss compared to the original MP3. At 128 kbps each, the loss is inaudible on consumer playback. For audiophile sources, do not chain lossy formats; keep one canonical lossless master and encode lossy versions from it.

The ringtone case (.m4r)

iPhone ringtones must be M4A under 40 seconds, renamed to .m4r. The workflow: convert MP3 to M4A here, open in QuickTime, trim to under 40 seconds, save, rename the .m4a extension to .m4r in Finder, drag the .m4r into the Finder iPhone sidebar (or the iPhone app on newer macOS). Without the M4A conversion step, none of this works because iPhone ringtones do not accept MP3.

The audiobook case (.m4b)

M4B is M4A with chapter markers, used for audiobooks in Apple Books. If you have a long-form recording you want as an audiobook with chapters, the workflow is: convert MP3 to M4A here, then use an audiobook tool (M4B Tool, Audiobook Binder on Mac) to add chapter markers and rename to .m4b. The MP3 to M4A step is the foundation; the chapter markers are added on top.

Frequently asked questions

Is MP3 to M4A conversion really free?

Yes. No account up to 25 MB, no watermark, no time limit.

What is the maximum file size?

25 MB anonymously, 60 MB with a free account.

Will the M4A sound worse than the MP3?

Theoretically yes, re-encoding any lossy format adds a small amount of loss. Practically, at 128 kbps AAC from a 128 kbps MP3, no human can hear the difference on consumer playback.

What is the difference between M4A and MP4?

M4A and MP4 are the same container format. The .m4a extension just signals "audio only" so iTunes knows what to do with it. Some players accept either extension.

How long does it take?

Seconds. A 25 MB MP3 converts in 3-10 seconds.

What quality do you output?

128 kbps AAC inside an M4A container, 44.1 kHz, source channel layout preserved.

Do you keep my files?

No. Upload deleted after conversion. Output purged within the hour.

Can I make an iPhone ringtone with this?

Indirectly. Convert MP3 to M4A, trim to under 40 seconds in QuickTime, rename the .m4a to .m4r, drop into Finder with your iPhone connected.

Will iTunes accept the result?

Yes. M4A is iTunes' native format.

My MP3 is already 320 kbps. Should I convert?

Only if you specifically need M4A for compatibility. The result will be 128 kbps AAC, technically a quality drop from 320 kbps MP3, but practically inaudible on most playback. To preserve the 320 kbps quality you would need a different converter that lets you set higher bitrates.

Do tags transfer?

Basic tags (title, artist, album) usually do. Cover art and detailed comments are flaky between MP3 ID3 and M4A iTunes metadata. Re-tag in iTunes or Mp3tag after conversion.

Can I batch convert?

Not yet on the free tier. Open multiple browser tabs to convert several files in parallel.