Convert MP3 to M4A MPEG Audio Layer III ↔ MPEG-4 Audio Free Online Secure
Your MP3 is decoded here in your browser and written out as M4A at the bitrate you pick. Nothing is uploaded, so there is nothing to delete afterwards.
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Where these formats come from
MP3 came out of years of research at Fraunhofer and was standardised in 1993 as part of MPEG-1. Its trick is psychoacoustic: it throws away the sound a human ear is unlikely to notice, mostly quiet detail masked by louder sound nearby, and it was that trick which made music small enough to travel over a modem. AAC — the thing inside an .m4a file — was designed as its successor and does the same job better at the same size. Ogg Vorbis appeared in 2000 as the patent-free answer, at a time when MP3 still had to be licensed. FLAC compresses without discarding anything, giving back the identical recording at about half the size, and WAV stores the raw samples with no compression at all.
Where you meet them
MP3 is still the format that plays on anything with a speaker, which is why it is the safe choice for sending something to a stranger. M4A is what Apple devices and most phones record and buy in. OGG travels inside games and open-source software. FLAC is for archiving a collection or ripping a CD when the original quality must be kept. WAV is the working format of recording and editing, where the file is opened and saved repeatedly and compression artefacts would accumulate.
Questions people ask
Will converting my MP3 to FLAC restore the quality?
No. FLAC will preserve perfectly whatever it is given, but what it is given here is already an MP3 — the detail removed when the MP3 was made is gone, and no later format can invent it back. You end up with a file several times larger that sounds exactly like the MP3. Converting to a lossless format is worth doing only from a lossless source; from an MP3, the honest answer is to keep the MP3.
Each time I convert, does it sound worse?
Between lossy formats, yes — a little. MP3, AAC and Vorbis each decide separately what the ear will not miss, and each conversion decodes the previous guess and makes a fresh one on top of it, so the losses accumulate. Converting once rarely matters; converting back and forth repeatedly does. Lossless formats have no such problem: WAV to FLAC to WAV returns exactly the samples you started with.
Does the file lose quality?
It depends on what the two formats can hold. Converting between formats that store the same thing — a PNG to a BMP, a WAV to a FLAC — loses nothing. Converting into a format that throws information away to save space, such as JPEG or MP3, loses a little every time, and converting back does not bring it back. Where a choice exists, this page errs towards keeping the original quality rather than making the smallest file.
Is my file uploaded anywhere?
No. The conversion happens inside your browser, on your own machine; the file never leaves it and there is no server here that could receive it. That is why a large file is limited by your own memory rather than by an upload, and why nothing you convert can appear in anybody's logs — including ours. The audio and video tools do fetch their conversion engine from this site the first time you use them, some thirty megabytes once; after that the work still happens entirely on your machine.
Why people convert MP3 to M4A
MP3 is the format everybody knows. For more than two decades it was the way music and recordings were stored, shared and carried around, and almost every device ever made can play it. M4A is its more modern cousin: the audio format of Apple's world, used by iTunes, iPhones and many other players, and based on a newer kind of compression that was designed to sound a little better at a given size. When someone needs to convert MP3 to M4A, it is almost never because the MP3 is broken. It is because something in their setup prefers or requires M4A.
The reasons are practical. A ringtone workflow that accepts only M4A. A podcast tool that wants its files in that format. A phone app or a car system that handles M4A better than MP3. A music library you are trying to keep uniform. In each case you have a perfectly good recording in one format and a program that would rather have another, and you want the change to be quick, private and free of surprises.
This page converts MP3 to M4A in your browser. Your audio is not uploaded anywhere, which matters for interviews, voice notes, meetings and anything else you would rather not hand to a stranger's server. Below you will find how the conversion works, what is kept, what is not, and, importantly, when it is worth doing at all.
How the conversion works
Decoded in your browser, written out as M4A
Your MP3 is opened inside your browser, decoded back into raw sound and then written out again as M4A at the bitrate you pick. Nothing is sent to a server, so there is nothing to delete afterwards. You drop the file, choose how much quality you want to spend on the new file, press the button and download the result.
Choosing the bitrate
The bitrate is the amount of data used for each second of sound. A higher bitrate keeps more detail and makes a larger file, and a lower one makes a smaller file with less detail. For speech, a modest bitrate is enough, and the file will be small. For music, choose a higher one. If the MP3 was recorded at a low bitrate to begin with, there is no point in choosing a very high one, because the detail that was lost earlier cannot be brought back.
A simple rule of thumb
Pick a bitrate that is similar to the one of the original MP3, or a little higher. Going far above it gives you a bigger file and no better sound; going far below it gives you a smaller file and clearly worse sound.
What is kept
Length, sample rate and channels
The full length of the recording is kept. So are its sample rate and both channels, so a stereo MP3 comes out as stereo M4A and the sound is not shortened, sped up or squeezed into one speaker.
A file that opens in anything current
The M4A that comes out opens in anything current: phones, tablets, computers, car systems and the common music programs. It is a mainstream format, and you are unlikely to meet a modern device that refuses it.
What you should know before you convert MP3 to M4A
It is a second round of loss
This is the most important thing on the page. Both MP3 and M4A are lossy formats. They save space by discarding parts of the sound that the ear is least likely to notice. When you convert MP3 to M4A, the audio is decompressed and then compressed a second time, and the second compression discards a little more. The result is a little worse than the MP3 was, at any bitrate. The difference is often very small and hard to hear, but it is real, and it is not reversible.
That is why this conversion is worth doing when something cannot read MP3, and not otherwise. If your player handles MP3 perfectly well, leave the file as it is. If you have the original recording in a lossless form, such as WAV or FLAC, make the M4A from that instead of from the MP3, and you will avoid the double loss.
Titles, artist names and cover art
Titles, artist names and cover art are not carried over. The new file contains the sound and little else. If you care about the tags, add them afterwards in your music program, or keep the MP3 beside the M4A so that the information is not lost.
The converter is fetched the first time
The converter itself is fetched the first time you use one of these audio pages, about nine megabytes, once. After that it stays in your browser, and later conversions start straight away. On a slow connection the first use takes longer.
How to convert MP3 to M4A here
Add your recording
Drop the MP3 onto the page or pick it from your device. It is read inside your browser and is not uploaded.
Pick the bitrate
Choose the bitrate that fits your purpose, higher for music you care about and lower for speech or for a small file.
Convert and download
Press the button, wait for it to finish and download the M4A. Play it from the beginning, check a passage in the middle and the end, and make sure the length matches the original.
A closer look at MP3 and M4A
Where the two formats come from
MP3 was standardised in the early nineties and became the format of the music download era. M4A is the audio-only version of the MPEG-4 container, and it normally holds sound compressed with AAC, a newer method that was designed to improve on MP3. At the same bitrate, AAC generally sounds a little cleaner, especially at lower bitrates. That is the argument for M4A. The argument for MP3 is that it plays everywhere, including in very old equipment.
Why the improvement does not reach you here
It might seem that, since M4A is the better format, converting to it would make an MP3 sound better. It does not. The detail the MP3 discarded is gone for good, and the new file can only store what remains. The improvement of M4A over MP3 applies when you encode from a clean source, not when you re-encode something that is already compressed. Treat this conversion as a compatibility step, and not as an upgrade.
Lossy and lossless in a sentence
A lossy format throws information away to save space and cannot get it back. A lossless format, such as FLAC or WAV, keeps everything. Moving from one lossy format to another always costs something, while moving from lossless to lossy costs only once.
Common situations in detail
Ringtones and alert sounds
Phones and tools that make ringtones often ask for M4A. To turn a short MP3 clip into one, convert MP3 to M4A, keep the clip short and check the result on the phone itself. For a ringtone the small loss in quality is rarely noticeable, since the sound plays through a small speaker.
Podcasts and voice recordings
Speech holds up very well at modest bitrates. If your podcast tool or hosting service prefers M4A, you can convert MP3 to M4A at a moderate bitrate and obtain a smaller file with sound that is perfectly clear. Keep the MP3 as a backup.
A uniform music library
Some people want everything in one format so that their library software treats every file in the same way. That is a fair wish, but a mixed library does little harm, and re-encoding hundreds of files costs quality for a small convenience. Convert only the files that actually give you trouble.
Cars, speakers and old players
Most equipment reads both formats. If one particular device skips or refuses MP3 files, try an M4A. If the device is very old, though, it may prefer MP3, and the safe answer is to test one file before converting a whole folder.
Questions people ask before converting
Will the sound get worse?
A little, yes. It is a second round of lossy compression, so the M4A is a little worse than the MP3 was, at any bitrate. For most listening the difference is small.
Should I convert my whole library?
No, unless something needs it. The conversion is worth doing when a device or program cannot read MP3. Otherwise leave your files alone.
Will the titles and artist names remain?
No. Titles, artist names and cover art are not carried over. Add them again in your music program if you need them.
Is my recording uploaded?
No. The conversion runs in your browser and the recording never leaves your device.
Can I turn the M4A back into MP3?
Yes, with M4A to MP3, though each step costs a little quality, so it is best not to go back and forth.
Choosing wisely when you convert MP3 to M4A
Think about the source first
Before you convert MP3 to M4A, ask where the MP3 itself came from. A file ripped long ago from a disc at a high bitrate has a lot left in it. A file saved from a low-quality stream, or already converted once from something else, has little. The new M4A can only be as good as what the MP3 still holds, so a poor source gives a poor result however you set the bitrate.
Match the bitrate to the content
Speech needs far less than music. A voice memo or a lecture is clear at a modest bitrate, and a bigger setting only inflates the file. Music with many instruments, a wide stereo picture or a quiet passage rewards a higher one. When you convert MP3 to M4A for a collection, you can pick one setting for the speech files and another for the songs.
Test one file first
Convert one recording, copy it to the device that gave you trouble and listen. If it plays, repeat for the others. If it does not, you have lost a minute and not an afternoon. This applies even more to a whole folder, where a mistake multiplies.
Keep the originals
Disk space is cheap and a second round of loss cannot be undone. Whenever you convert MP3 to M4A, keep the MP3 in a folder of its own. If you later find a better way to do the job, or a device that prefers the MP3 after all, the original is still there. For some listeners, a good compromise is to keep the lossless source, if one exists, as the master, and make both the MP3 and the M4A from it.
Mind the tags
Because titles, artist names and cover art are not carried over, a folder of converted files can look anonymous in a player. Rename the files before you convert MP3 to M4A so that the names themselves say what each one is, and add proper tags afterwards in a music program if you want them.
A note on very small files
Short clips, such as alerts, jingles or a few seconds of speech, are less affected by the second round of compression than long music tracks, since there is less sound for any artefact to hide in. They are a good first thing to try if you are curious how the conversion behaves on your own equipment.
Privacy and handling
Why local conversion matters for audio
Audio files often hold voices, and voices are personal: an interview, a meeting, a message from a relative, a lesson. Many online converters upload your file to a server, process it and send it back, and for a while a copy lives on a machine you do not control. Here, your own browser does the work, and the recording stays on your device.
What happens when you leave
When you close the page, the converted file disappears from the browser, so download it first. The converter, about nine megabytes, stays in your browser storage so the next conversion starts faster. Your recordings are never kept.
If something goes wrong
The page freezes with a very long recording
Everything happens on your device, and a recording of several hours may be too large for a phone to handle. Try again on a computer, or split the recording into shorter parts first.
The M4A does not play on a device
Try it in another player first. Some very old devices do not read M4A, and in that case the original MP3 is the safer choice. Keep the MP3 in any case.
The sound is quieter, or has a slightly different character
That is the second round of compression at work. Try a higher bitrate, and if possible convert from a lossless original instead.
Related audio conversions
The audio tools of this site cover the other common pairings. To go the opposite way, use M4A to MP3. For a different open format, MP3 to OGG works in the same way, and for lossless storage there is MP3 to FLAC, which keeps what the MP3 still holds without losing any more. For editing programs that want uncompressed sound, MP3 to WAV is the right step, and WAV to MP3 and FLAC to MP3 make small files out of lossless ones.
A worked example
Say you have a voice memo recorded years ago as an MP3 of 12 megabytes, and the podcast app you want to use asks for M4A. You drop the file here, choose a moderate bitrate suited to speech and press the button. A few seconds later you download an M4A of about 6 megabytes with the same length and both channels. It plays in the app. The MP3 stays on your computer, in case you ever need the original.
A short checklist
Before converting
Check that the device or program really needs M4A. Find the original recording if you still have it. Decide on the bitrate.
While converting
Stay on the page until the file is ready. Do not start other heavy tasks on a phone.
After converting
Download the M4A, listen to the beginning and the end, and keep the MP3 until you are sure the new file does the job.
Common mistakes
Converting to improve the sound
Do not convert MP3 to M4A hoping for better quality. It cannot give it to you, and it takes a little away.
Converting back and forth
Each lossy conversion costs something. Choose the format you need and keep it, and work from the original recording when you have one.
Throwing away the MP3
Keep it. It holds the tags and is the copy that plays everywhere. The same advice applies to other audio pairs, such as OGG to MP3 and WAV to MP3.
Your recording stays on your device
The conversion happens locally. Your recording is read by your own browser, converted there and handed back. Nothing is uploaded, so no copy ends up on a server and nobody else can listen to it. For voices and private recordings, that is the safe way to convert MP3 to M4A.
Summary
To convert MP3 to M4A here, drop the file, choose a bitrate and press the button. Your MP3 is decoded in your browser and written out as M4A. The full length, the sample rate and both channels are kept, and the file opens in anything current. Because both formats are lossy, this is a second round of loss: the result is a little worse than the MP3 was, at any bitrate, so it is worth doing when something cannot read MP3 and not otherwise. Titles, artist names and cover art are not carried over. The converter is fetched the first time, about nine megabytes, once. Nothing leaves your device.