M4A to MP3
Convert a voice memo or iTunes track for something that only plays MP3.
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or drag them here
M4A or AAC · one or many
- Takes
- M4A, AAC, and M4B, plain AAC or the HE-AAC that podcasts and radio streams use. Video files work too — an MP4 or MOV is accepted and its picture discarded — and several files can go through at once on the same settings.
- Size
- No cap, and nothing is uploaded, so the only ceiling is your own tab's memory. The source is read off disk in pieces rather than loaded whole; what is held is the MP3 being written, about 1.4 MB per minute at 192 kbps. A two-hour audiobook is unremarkable — a 12-minute file re-encodes in around five seconds, and it scales from there.
Your file never leaves your browser during processing
How it works
To convert an M4A file to MP3, drop it onto this page and pick a bitrate — the audio is decoded and re-encoded by your browser and nothing is uploaded. Because M4A is already compressed, this is a second lossy pass, so it is worth doing for compatibility rather than for quality or size.
An M4A file is an MP4 container holding AAC audio — the format an iPhone writes when you record a voice memo, and what Apple Music sells. AAC is a better codec than MP3: at the same bitrate it sounds slightly closer to the original. The reason to convert anyway is that a lot of hardware never learned to read it — older car stereos, DJ software, dictation systems, some podcast uploaders and voicemail systems.
This page decodes the AAC with the decoder built into your browser and re-encodes it as MP3. That is a genuine round trip: the audio is expanded back to samples and squeezed again by a different codec that makes different choices about what to discard. The result is a second generation, and no bitrate setting makes it identical to the source. Picking a bitrate at or slightly above the original — most voice memos are 64 kbps, most music around 256 kbps — keeps the second pass from adding much of its own damage, which is why this page will not preselect a bitrate higher than what your file already has.
Everything happens in your browser. Your file is read locally and the MP3 encoder is a WebAssembly module that loads once before processing starts, so the counter under the tool watches the conversion itself and stays at zero bytes sent.
One caveat about browsers: AAC decoding relies on the codecs your operating system provides. Chrome, Edge, and Safari have it everywhere. Firefox usually does, but some Linux builds ship without it — the tool checks your file rather than guessing, and tells you plainly if the decoder is missing instead of failing halfway through.
FAQ
Will converting M4A to MP3 lose quality?
Yes, a little. The M4A is already lossy, so decoding and re-encoding it as MP3 discards a second round of detail. It is usually inaudible on speech and slight on music at a matching bitrate, but it is not reversible — keep the M4A if you might need it again.
Should I use a higher bitrate to avoid losing quality?
No. A higher bitrate cannot recover detail the M4A already discarded; it just makes a bigger file. Match the source bitrate or stay close to it. This page will not preselect a setting above what your file contains.
Will the file get smaller?
Usually not by much, and it can get larger. AAC is more efficient than MP3, so the same audio needs a slightly higher MP3 bitrate to hold up. Converting for size is the wrong reason to be here; converting for compatibility is the right one.
Does this work with iPhone voice memos?
Yes. Voice memos are M4A files containing AAC, typically mono at 64 kbps, and they convert quickly. Leaving the mono option on keeps the file small since there is no stereo information to preserve.
Why does it say my browser cannot decode the file?
Because AAC decoding depends on codecs supplied by your operating system, and some Firefox builds on Linux ship without them. Chrome, Edge, or Safari will convert the same file. The check runs against your actual file rather than assuming from the browser name.