M4A vs MP3: what is the difference?
M4A is the audio file iPhones, iTunes and many recorders make. MP3 is the format everything plays. Here is what separates them, with sizes measured on the same recordings.
- Never uploaded
- No size limit
- No sign-up
- Free
Keep this tab open and in front. Browsers slow down background tabs.
Quick answer: An M4A file usually holds AAC sound, which is more efficient than MP3: at the same bitrate the files are the same size (one minute of music: 0.98 MB as 128 kbps M4A, 0.96 MB as 128 kbps MP3), but the M4A sounds slightly better at 128 kbps and below. MP3 plays on more old devices. Keep M4A for iPhone and Mac use; convert to MP3 when an old player, car stereo or website will not take M4A.
Updated
Keep M4A when
- You listen on an iPhone, Mac, Android phone or in a browser: they all play it.
- It is an iPhone voice memo you only need to keep or send to another phone.
- It is a lossless Apple file (ALAC): converting would throw detail away.
Convert to MP3 when
- An older car stereo, MP3 player or speaker does not list it.
- A website or app only accepts MP3, such as some podcast hosts and school portals.
- You send it to someone and do not know what they will play it on.
The same recordings, measured
| Recording | M4A (AAC) | MP3 |
|---|---|---|
| 1 min of music, 128 kbps | 0.98 MB | 0.96 MB |
| 1 min of music, 256 / 320 kbps | 1.93 MB | 2.40 MB |
| 1 min of speech, mono, 64 kbps | 0.50 MB | 0.48 MB |
One minute of the Sintel trailer soundtrack (stereo, 44.1 kHz), made with standard free software on 20 October 2026. Sintel © Blender Foundation, CC BY 3.0. One minute of a person reading aloud (mono), made with standard free software on 20 October 2026.
How it works
- Drop your audio fileM4A, WAV, FLAC, OGG and more, any length. It stays on your computer.
- Pick the quality"Very good" suits speech and most music; "Best" for music you care about.
- Download the MP3Plays on every phone, computer, car stereo and audio editor.
M4A is a wrapper, AAC is the sound
M4A is the audio-only kind of MP4 file. Almost always the sound inside is AAC, a lossy format like MP3 but newer and more efficient. Apple also uses M4A for ALAC, its lossless format, so an M4A from a CD rip in Apple Music may be lossless and five times bigger. The converter above handles both.
Why your M4A will not play
Usually the player only knows MP3: many car stereos, cheap MP3 players and some voice-mail or upload forms. Windows 10 and 11 play M4A in the Media Player app, and every phone does. If a file plays nowhere at all, it may be damaged rather than the wrong format.
Converting without losing more than needed
Pick a bitrate at or above the M4A's. Voice memos are small, so the "Speech" setting is plenty; for music, use "Very good" or "Best". Converting never improves the sound, so keep the M4A as well.
Measured, not promised
From our tests in Chrome on a 2019 Intel MacBook, October 2026. See all results.
Why your audio never leaves your computer
Online converters upload your file to their servers, convert it there and send it back. That is slow for long recordings, so free plans cap the length or the number of files, and your recording sits on someone else's computer.
Here your own computer does the work, inside this tab. Nothing is uploaded, so there is nothing to cap: no length limit, no daily limit and no sign-up.
Questions
Is M4A better quality than MP3?
At the same bitrate, slightly, because AAC is more efficient. At 256 kbps and above most people hear no difference. A lossless (ALAC) M4A is better than any MP3.
Are M4A files smaller than MP3?
Only when they use a lower bitrate. At the same bitrate they are the same size, as the table shows.
Can I convert several M4A files at once?
Yes. Choose or drop them together; they are converted one after another and download one by one or as a ZIP.
Is it really free?
Yes. Your computer does the work, so a file costs us nothing to convert. No account and no limits.
Is my file uploaded?
No. It is converted inside this browser tab and saved straight back to your computer.
Which browsers work?
Recent Chrome, Edge and Safari on a computer.
Can I use a video file?
Yes. Drop a video and you get its sound.