Convert M4A to MP3 with Audacity

By the M4AtoMP3.org editorial team · October 21, 2026 · 10 min read

Audacity is a free audio editor rather than a converter, which makes it the right tool when you want to do something to the audio before saving it as MP3 — cut out the first two minutes of a lecture, remove a hum, boost a quiet interview or split a long recording into tracks. Straight conversion works too, but it involves one extra step the first time: installing the FFmpeg library so Audacity can read M4A at all. This guide covers that setup, the export settings that matter, and batch conversion with Macros.

If you only need a straight conversion with no editing, the browser-based M4A to MP3 converter is quicker and nothing is uploaded.

Step 1: install Audacity and the FFmpeg library

1. Download Audacity from audacityteam.org (version 3.x). Avoid third-party download sites, which sometimes bundle adware.
2. Audacity can export MP3 out of the box, but to import M4A/AAC it needs the separate FFmpeg library. Open Edit › Preferences › Libraries (on Mac: Audacity › Settings › Libraries).
3. If the FFmpeg Library line says not found, click Download and follow the link to the FFmpeg installer recommended by the Audacity manual for your system.
4. Install it, restart Audacity and check Libraries again. It should now show a version number.

On Linux, Audacity from your distribution usually picks up the system ffmpeg automatically; Flatpak builds include it.

Step 2: open the M4A file

Use File › Open or drag the file into the window. Audacity decodes the whole file into its own uncompressed format, so a long recording takes a moment and uses disk space for temporary data (roughly 10 MB per stereo minute). You will see the waveform once it loads.

If you get “Audacity did not recognise the type of this file”, the FFmpeg library is not installed or not detected — go back to Step 1. If the file still fails, it may be damaged or not really M4A; see why won’t my M4A file play.

Step 3 (optional): edit before you export

The reason to use Audacity is editing. The most useful quick fixes:

• Trim the start and end: select the region with the mouse and press Delete.
• Even out the volume: select all (Ctrl/Cmd+A) and use Effect › Volume and Compression › Normalize to bring peaks to −1 dB, or Loudness Normalization to target a perceived level such as −16 LUFS for podcasts. Our guide to normalising audio volume explains which to use.
• Reduce background noise: select a few seconds of “silence” with only the noise, choose Effect › Noise Removal and Repair › Noise Reduction › Get Noise Profile, then select everything and apply it with moderate settings (6–12 dB). Too much makes voices sound watery.
• Convert to mono: for a voice recording, Tracks › Mix › Mix Stereo Down to Mono halves the file size of the finished MP3 at the same bitrate.
• Split into tracks: add labels with Ctrl/Cmd+B at each split point; you will export them as separate files in Step 4.

Step 4: export as MP3

1. Choose File › Export Audio… (in older versions File › Export › Export as MP3).
2. Set Format to MP3 Files.
3. Pick the Bit Rate Mode and quality (see below).
4. Choose a file name and folder, then click Export.
5. The Edit Metadata dialog appears. Check Title, Artist, Album and Track Number — these become the ID3 tags — then click OK.

To export labelled sections as separate files, choose File › Export Other › Export Multiple (or the “Multiple files” option in the 3.4+ export dialog), split by labels, and name files by label text or number.

Export settings explained

Channel Mode “Joint Stereo” is the right choice for almost all music; it saves bits on content that is the same in both channels without reducing quality. Use “Stereo” only if you know you need fully separate channels.

Not sure about CBR vs VBR? See CBR vs VBR MP3.

Batch convert many M4A files with a Macro

Audacity can apply the same steps to a stack of files:

1. Open Tools › Macro Manager and click New. Name it, for example, M4A to MP3.
2. Click Insert and add Export as MP3. Optionally add steps before it, such as Normalize or Loudness Normalization.
3. Click Edit on the Export step if you want to set a specific quality; Audacity otherwise uses the last settings you exported with, so do one manual export first with the settings you want.
4. Click OK to save the macro.
5. Open Tools › Apply Macro › Palette…, choose your macro and click Files…. Select all your M4A files.

Audacity creates a folder called macro-output next to the source files and saves the MP3s there with the same names. For hundreds of files, ffmpeg is faster because it does not render waveforms, but the Macro approach is great when every file needs the same clean-up.

Common Audacity problems

Export is greyed out or fails with “could not open file”

Check that the destination folder exists and is writable, and that the file name does not contain characters Windows does not allow (\ / : * ? " < > |).

The MP3 is louder or quieter than the original

You applied an effect, or the project rate differs from the original. If you want an untouched conversion, do not apply any effects and leave the project rate at the file’s original rate (shown at the bottom left).

Clipping or distortion after normalising

Normalising to 0 dB can cause clipping once the MP3 encoder adds tiny overshoots. Normalise peaks to −1 dB instead.

Cover art disappears

Audacity does not carry embedded artwork through to export. Add it back with a tag editor; our metadata guide lists good free ones.

Huge temporary files fill the disk

Audacity stores projects uncompressed. Close projects you do not need, and choose “Don’t save” when closing after an export if you will not edit the file again.

Is Audacity the right tool for you?

Choose Audacity when you need to change the audio: trimming, noise reduction, levelling, splitting. Choose a straight converter when you only need a different format: our online converter for occasional files, VLC if it is already installed, or ffmpeg for automation.

Keyboard shortcuts that speed things up

• Space — play/stop, to check your edits.
• Ctrl/Cmd+A — select the whole track before applying an effect.
• Ctrl/Cmd+B — add a label at the cursor (for splitting tracks).
• Ctrl/Cmd+Shift+E — open the export dialog.
• Ctrl/Cmd+1 / 3 — zoom in and out on the waveform.

Keep the original until you have checked the MP3

Audacity never changes the M4A on disk — it works on a copy in its project data — but it is still good practice to listen to the start, middle and end of the exported MP3 before deleting anything. Long recordings occasionally import with a glitch if the M4A had a damaged section, and you want to find that out while the original still exists.

Summary

Install Audacity and its FFmpeg library, open the M4A, make any edits, then use File › Export Audio with MP3 selected. Use the Standard or Extreme preset for music and 96–128 kbps mono for speech, fix up the tags in the Edit Metadata dialog, and use a Macro when you want the same processing on many files.

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