Turn an M4A (AAC) file, like a voice memo from an iPhone, into a universally compatible MP3.
The M4A to MP3 converter turns M4A audio (MPEG-4 audio container, normally AAC) into MP3 (MPEG-1/2 Layer III) directly in your browser. M4A (Apple’s AAC container) does not play everywhere; MP3 does.
M4A is Apple’s default audio file type (iTunes, Apple Music downloads, Voice Memos) — more efficient than MP3 at the same bitrate. MP3 is the most universally supported lossy format; plays on virtually every phone, car stereo, browser and editor. Both M4A and MP3 are lossy, so this is a transcode: some extra quality is lost. Pick a bitrate at or above the original’s to limit the damage, and keep the original file. Voice Memos recorded on an iPhone are M4A, which is why this conversion is so common.
Your file is decoded to 32-bit floating-point samples by the browser’s own audio decoder — and at the file’s own sample rate, not a resampled one. You can optionally resample or switch channels. It is then encoded to MP3 on your device; for a lossy target the result is decoded again for the preview, so you hear what you will get. Typical size: about 1 MB per minute at 128 kbps, 2.4 MB at 320 kbps.
Source format facts: M4A files are lossy; usual bandwidth: typically 20 kHz at 128–256 kbps. Target facts: MP3 is lossy; usual bandwidth: typically low-passed at 16–20 kHz depending on bitrate.
Convert .m4a recordings for Windows and Android.
Make iTunes files work on older players.
Some head units only read MP3.
Send files anyone can open.
| From | M4A — MPEG-4 audio container, normally AAC |
|---|---|
| To | MP3 — MPEG-1/2 Layer III |
| Direction | lossy → lossy |
| Typical size | about 1 MB per minute at 128 kbps, 2.4 MB at 320 kbps |
| Tags | M4A: MP4 atoms → MP3: ID3 |
Slightly — it is lossy to lossy; a high bitrate keeps it inaudible.
Audio is converted; use the Metadata Editor to add MP3 tags.
M4A is common on Apple devices but isn't universally supported by every app or older device — MP3 plays back almost everywhere.
Going to WAV is lossless. Going to MP3 uses a standard 192kbps encode by default (adjustable), which is transparent for most listening but is a lossy step if your source was uncompressed.
No — the file is decoded and re-encoded entirely in your browser using the Web Audio API and, for MP3, a small bundled encoder. Nothing is sent anywhere.
This tool runs entirely in your browser using the Web Audio API. Nothing is uploaded, stored or shared — there is no server to send your file to, so it works offline once the page has loaded.
Be the first to share your experience with this tool — your feedback helps others.