Is this M4A to AAC converter really free?

Yes. Up to 5 files at a time, no signup, no catch. The free tier adds a small watermark to image output — Pro ($9.99/mo or $49/yr) removes it, raises the file size limit to 500 MB, and unlocks unlimited batch conversion.

Are my files uploaded to a server?

No — and you can verify it yourself. Open DevTools → Network tab, then convert a file. You'll see zero upload requests. Everything runs right in your browser. We never see your files.

How long does conversion take?

Usually 1–3 seconds for a typical file. The very first conversion on a fresh page load may take 5–20 seconds while the converter engine loads — after that it's instant. Your CPU does all the work locally.

What is the file size limit?

Free: up to 10 MB per file, 5 files per batch. Pro: up to 500 MB per file, unlimited batch. If you're working with large videos or RAW photos, Pro is built for that.

Can I batch convert multiple M4A files at once?

Yes — drop multiple files at once (or Ctrl/Cmd+click to select them) and they all convert in parallel. Free accounts handle up to 5 files per batch; Pro has no limit.

What bitrate will the converted audio use?

We default to 192 kbps for MP3, 128 kbps for OGG/Opus, and 320 kbps for M4A/AAC. These settings are perceptually transparent — most listeners can't tell the difference in a blind test.

Will my metadata (ID3 tags, album art) be preserved?

Yes, when both formats support it. Tags carry over on conversions like MP3→M4A or FLAC→MP3. WAV has limited tag support, so some metadata may not transfer.

What's the actual difference between M4A and AAC files?

M4A is an MP4 container holding AAC audio data. A bare .aac file is the raw AAC bitstream. The audio content and quality are identical; only the wrapper changes. Some broadcast systems and embedded devices only accept raw AAC.

Does converting M4A to AAC lose any quality?

No quality loss occurs if the converter does a container-only remux (which it does for M4A-to-AAC). The AAC audio data is extracted without re-encoding.

How private is this converter?

Completely private — by design, not policy. There is no upload endpoint. Files are processed right inside your browser tab and disappear the moment you close it. We collect only anonymous page-view counts; your file content is never seen or stored.

M4A to AAC Converter — Free, Online, No Upload

How to convert M4A to AAC online

1
Drop your M4A file
Drag and drop your MPEG-4 Audio file onto the converter, or click to browse your files. You can select up to 5 at once. Nothing leaves your device — conversion happens right here in the browser.
2
Hit Convert — it happens locally
Click Convert and watch it go. There's no upload, no server queue, no waiting. The converter runs MPEG-4 Audio → Advanced Audio Coding entirely in your browser tab. Most files finish in 1–3 seconds.
3
Download your AAC
Your Advanced Audio Coding file is ready. Click Download, or grab a ZIP if you converted a batch. Close the tab and everything disappears — no copies kept anywhere.

M4A vs AAC: format overview

M4A

MPEG-4 Audio

Apple / MPEG Group · 2001

Compression: lossy
Transparency: No

✓ Better quality than MP3 at same bitrate (AAC codec)
✓ Native Apple ecosystem support
✗ Not universally supported on all Windows/Linux players

AAC

Advanced Audio Coding

Dolby, Fraunhofer, Sony, Nokia · 1997

Compression: lossy
Transparency: No

✓ Successor to MP3 — better quality at same bitrate
✓ Native support across Apple, Android, YouTube

M4A magic bytes: 00 00 00 xx 66 74 79 70 4D 34 41

AAC magic bytes: FF F1 (ADTS) / 00 00 00 xx 66 74 79 70

Why convert M4A to AAC?

M4A and AAC are the same audio codec in different packaging. An M4A file is simply an MP4 container with an AAC audio track inside — the audio data is identical. The distinction only matters when a piece of hardware or software cares about the container rather than the codec. Most consumer apps handle both interchangeably, but certain systems do not.

Broadcast delivery systems, smart TV apps, automotive infotainment systems, and some embedded media players are built to read raw AAC bitstreams (.aac files) rather than MP4-wrapped containers (.m4a files). If you're delivering audio to a DAB+ radio system, an HLS streaming pipeline that ingests bare AAC, or a device that parses codec headers strictly, a raw .aac file is what the system expects. The conversion is a container remux — the audio data inside is extracted and written to the new format without any re-encoding, so there is no quality change whatsoever.

The resulting AAC file will be virtually the same size as the M4A source. The audio quality is bit-for-bit identical. What changes is the wrapper — from an MP4 container to a raw AAC bitstream. Note that some metadata (album art, extended tags) stored in the M4A container may not carry over, since raw AAC has limited metadata support compared to the MP4 container format.

Quality & file size: M4A to AAC

Typical file sizes: M4A 3–6 MB → AAC 2–5 MB.

Both M4A and AAC use lossy compression. We transcode at high quality settings (equivalent to AAC's recommended web quality) to minimize generational loss.

Color depth: M4A supports standard color, AAC supports standard color.

Transparency: M4A does not support transparency. AAC does not support transparency — transparent areas become solid white.

Frequently asked questions

Privacy: how FormatDrop handles your files

Your M4Afiles are converted 100% inside your browser. They are never uploaded to our servers, never stored, and never seen by anyone other than you. This isn't a privacy policy claim — it's an architectural guarantee: our server has no endpoint that receives file bytes.