Drop a Voice Memo or any .m4a and it is re-encoded to MP3 on your device — never sent to a server.
Drop a Voice Memo or any .m4a and it is re-encoded to MP3 on your device — never sent to a server.
Convert M4A audio to MP3 in your browser. M4A is what iPhones, Voice Memos, and iTunes produce — and what plenty of players, editors, car stereos, and upload forms still refuse. Drop the file and GhostAudio re-encodes it to universally compatible MP3 on your device. No upload, no signup, no length cap — and voice memos, which often hold things you don't want on someone's server, never leave your device.
M4A is a container, not a codec — it usually holds AAC, a genuinely better codec than MP3 at the same bitrate. The reason to convert is almost never quality; it's compatibility: voice recorders, car head units, gym equipment, older DAWs, podcast ingestion tools and embedded players still expect MP3. That's the trade this tool makes: a small quality cost for a file that plays everywhere.
How it works
Drag in the .m4a file — a Voice Memo, an iTunes track, a recording. It opens in the GhostAudio studio with Convert to MP3 pre-selected.
ffmpeg decodes the M4A and encodes an MP3 in your browser — nothing is sent anywhere.
Save it — it now plays everywhere, from decade-old car stereos to every editor ever written.
This is a lossy-to-lossy conversion
The AAC inside the M4A is decoded and re-encoded as MP3, so you're compressing already-compressed audio. For speech this is inaudible; for music at low bitrates it can be noticeable. Convert from an original lossless source where you still have one.
iPhone voice memos are M4A
Which is why this page exists. Voice Memos exports .m4a, and a lot of transcription services and older systems will not accept it. Note that long recordings can be large — on a phone, memory limits apply.
Metadata may not survive
Track titles, artwork and chapter markers live in container-specific atoms. Basic tags usually carry across; artwork and chapters often don't.
No — the conversion runs in your browser via WebAssembly ffmpeg. Voice memos stay on your device.
Both formats are lossy, so re-encoding costs a little — inaudible for speech and voice memos, minor for music at a decent bitrate.
Apple defaults to AAC audio in an M4A container — technically excellent, just less universally supported than MP3.
No fixed cap — hour-long recordings convert fine on a typical device.
No — it can only lose information, never add it. Convert for compatibility, not for quality. If the M4A already plays where you need it, keep it.
No. The audio engine runs in your browser as WebAssembly, so the recording never leaves your device. That matters for voice memos, which are frequently personal.
WAV to MP3
Encode a huge WAV as an MP3 — 5–10× smaller, sounds the same.
Trim audio
Cut silence or clip a segment on the waveform, locally.
Compress audio
Re-encode at a lower bitrate — speech shrinks dramatically.
FLAC to MP3
Share-sized MP3s from lossless FLAC.
Opus to MP3
WhatsApp and Telegram voice notes to MP3.
Every GhostAudio tool runs entirely in your browser. Your file is never uploaded — there's no upload endpoint to send it to.