M4A / Voice Memo to MP3
Drop an .m4a or a Voice Memo. Pick a bitrate. This tab writes an MP3. The file stays here. Re-encoding does not add detail.
Drop .m4a, .m4b or .aac
Up to 50 files, 80 MB each. A folder is fine. Nothing is uploaded.
The file stays in this tab
A Voice Memo is often a meeting or a session you would not put on a random converter. Most "m4a to mp3" pages are a form in front of a server. You drop the file and they keep it. Then they ask for an account before you get an MP3 back. This page does not do that.
Once the JavaScript has loaded, the recording stays in memory here. The browser decodes the AAC. A LAME encoder, about 130 KB gzipped, writes the MP3. You will see that first load. After that it stays in the tab. Mixpanel and Google Analytics load with the rest of Softery.io. They see that someone opened the tool. They do not get the file name or the bytes. If you came here because a privacy page promised zero third-party scripts, that is not this site, and I will not write that sentence.
Voice Memo mode is smaller, not smarter
An iPhone Voice Memo is usually AAC in an .m4a wrapper. Cars and a lot of older players still want MP3. Tick Voice Memo mode and the encode is mono at 64 kbps and 22,050 Hz. That is a size choice for speech. It is not a cleaner recording. Re-encoding does not add detail.
Leave the box unticked and pick 64, 96, 128, 192, or 320 kbps. 128 is the default. The line under the radios shows the duration this tab read, and an estimated byte count from bitrate times 125 bytes per second. The file you download is measured after encode. The estimate can miss. Tags on the original are not copied, so the MP3 does not carry the phone's title or location fields.
Folders and names
Drop one file or a whole folder. This run takes 50 files at most, each 80 MB at most. A PDF in the same drop is skipped. An MP3 is already an MP3. A clip with a picture track belongs on Compress Video for Discord. Each result is named from the original stem and the bitrate, like Interview-128kbps.mp3. Two files with the same stem get -2 and -3. A batch downloads as converted-N-files.zip.
Hit Convert and wait. There is a Stop button. A long memo can hitch the tab or run out of memory, because the work shares RAM with the rest of the page. Play the result in this tab before you save it. The sample is a two-second tone named sample-voice-memo.m4a, so you can see the duration line without using a real recording.
What this page will not do
It will not transcribe the file. Live dictation is Speech to Text, and that page listens to the microphone. It will not pull sound out of a video. It will not claim the MP3 is "better" than the memo you dropped. Lossless Apple memos may fail to decode. If they do, the page says so.
The encoder is LAME, through Mediabunny's MP3 package, MPL-2.0. LAME asks for a shoutout: lame.sourceforge.io. This page does not ship FFmpeg compiled to WebAssembly.
Common questions
Does this page upload my recording?
No. The file stays in this tab. After the page has loaded, decode and encode run in JavaScript here. Mixpanel and Google Analytics load with Softery.io. They see that someone opened the tool, which bitrate moved, and whether a download happened. They do not get the file name or the sound.
Will the MP3 sound better than the Voice Memo?
No. Re-encoding cannot add detail the original did not have. A lower bitrate makes a smaller file and throws more of the original away. 128 kbps is the default because it is a common size for speech. Voice Memo mode is mono at 64 kbps.
What if this tab cannot decode the file?
AAC Voice Memos usually work. A lossless memo may not. If the codec is one this tab cannot read, you get a plain error and the file is not sent anywhere. A file with a picture track belongs on Compress Video for Discord.
Where do the settings live?
Bitrate and Voice Memo mode are stored in this browser under softery.m4a-to-mp3.settings. The recordings are not stored. The settings link copies those knobs in the URL and never the file. Clear the site data, or hit Clear settings, and the knobs go back to 128 kbps.
Nearby tools
Words from talking, live, belong on Speech to Text. A clip that is too big for Discord belongs on Compress Video for Discord. Both stay in the tab.
The longer version of why a Voice Memo stays on this device is in The Memo Stayed on This Phone.