Audio tool
Convert M4A to MP3
M4A is what iPhones and Macs record by default, and it is the format most likely to be refused by something else. This converts it to MP3, which nothing refuses.
- 100% free
- No signup
- Batch convert
Drop your MP4 files here
or click to browse from your device
Supports MP4 · Max 200 MB per file · Up to 100 files
You can also paste a copied image with Ctrl+V / ⌘V
Conversion settings
MP3 is lossy, so this is a size-versus-quality trade. 192 kbps is transparent to most listeners on most material.
- Secure & privateYour files are never shared
- Lightning fastMost images in under a second
- High qualitymozjpeg and libvips under the hood
- Works everywhereAny device, any browser
Input, output and limits
Every figure below is read from the same configuration the server enforces, so this page cannot promise a limit the system will refuse.
- Input formats
- M4A
- Output format
- MP3What is MP3?
- Maximum file size
- 200 MB per file
- Maximum duration
- 60 minutes
- Batch processing
- Yes — several files at once, downloaded as one ZIP
- Price
- Free, with no account and no watermark
- Processing
- On our own server, then deleted automatically
- Engine
- FFmpeg
- File retention
- Upload and result both deleted after 24 hours
Output quality
The AAC stream is decoded once and re-encoded with LAME at your chosen bitrate. Sample rate, channel count and duration are carried over unchanged, so the MP3 is a frame-accurate substitute for the original when syncing against anything else. Basic tags survive; embedded artwork does not, because it travels as a one-frame video stream that some players choke on. The unavoidable cost is generational loss — M4A is already lossy, so this is a second lossy pass. At 192 kbps and above that is inaudible in practice, but if the M4A is your only copy of something irreplaceable, keep it alongside the MP3 rather than instead of it.
See what this tool actually did to real files — median size change, speed and sample size, published whichever way the numbers fall.
Common use cases
Voice memos going to a transcription service
Many only accept MP3 or WAV, and M4A is what your phone recorded.
Playing Apple recordings on other hardware
Car stereos, older MP3 players and some TVs never learned M4A.
Attaching audio to a form or portal
Upload validators frequently list MP3 and nothing else.
Interviews and lectures
128 kbps keeps speech clear at a fraction of the size.
Settings you can change
Quality
320 kbps — highest, biggest file · 256 kbps — very good · 192 kbps — the usual choice · 128 kbps — small, fine for speech · 96 kbps — voice notes only
MP3 is lossy, so this is a size-versus-quality trade. 192 kbps is transparent to most listeners on most material.
Troubleshooting
- My file is refused even though it ends in .m4a
- Some tools write .m4a files with a generic MP4 brand, which is indistinguishable from a video file by its header. Try MP4 to MP3 instead — it handles the same content.
- The result sounds slightly duller than the original
- That is generational loss from a second lossy encode. Raise the bitrate to 256 or 320 kbps and it will be inaudible.
- The album art disappeared
- Cover art is dropped deliberately — it is stored as a video stream and some players reject files that carry one.
Something else went wrong? Tell us what happened — a person reads every report, and that is how this list gets longer.
Privacy and file deletion
- Stored under a random nameUploads have no connection to the file name you sent and are never served from a public directory. This tool accepts files up to 200 MB, several at a time.
- Deleted on a timerUploads are removed within 2 hours and finished results within 24 hours, whichever comes first.
- Nobody looks at themNo one browses uploads, nothing is shared with third parties, and no file is used to train anything. The only thing kept past deletion is the size and timing of the job.
- Encrypted in transitEvery request runs over HTTPS, so the file is encrypted between your device and our server.
Full privacy policyHow the system is builtWhat we measure, and why it is kept
Frequently asked questions
Browse video toolsWhy does my iPhone make M4A files?
Apple has used M4A — AAC audio in an MP4 container — as the default for Voice Memos and iTunes purchases for years. It is a technically better format than MP3 at the same bitrate. The trouble is only that older players, transcription services and upload forms often do not accept it.
Does the conversion lose quality?
A little, unavoidably. Both formats are lossy, so decoding AAC and re-encoding as MP3 goes through a second round of compression. At 192 kbps or above the difference is inaudible on normal listening equipment. Keep the M4A if you might need to re-convert later.
Will my voice memo still be the right length?
Yes. Length, sample rate and channel layout are preserved exactly, which matters if you are lining the audio up against video or a transcript.
Is my file uploaded?
Yes — FFmpeg cannot run usefully in a browser tab for files this size. Stored under a random name, never listened to by a person, deleted within 24 hours.
How long does my video stay on your server?
Your upload and the finished file are both deleted 24 hours after the job starts. This tool accepts files up to 200 mb and 60 minutes long. Nothing is shared with anyone and there is no account for it to be attached to; while a job is live we may open it in our own admin area to check the encode came out clean.