Is this MP4 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 MP4 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.

Does extracting AAC from MP4 cause any quality loss?

No — MP4 videos almost always contain an AAC audio track. Our converter extracts it directly without re-encoding, preserving the original audio quality exactly.

Can I use the extracted AAC in editing software?

Yes — raw AAC files work in Adobe Audition, DaVinci Resolve, and most professional audio and video editors. Rename to .m4a if your software prefers that extension.

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.

MP4 to AAC Converter — Free, Online, No Upload

How to convert MP4 to AAC online

1
Drop your MP4 file
Drag and drop your MPEG-4 Part 14 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 Part 14 → 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.

MP4 vs AAC: format overview

MP4

MPEG-4 Part 14

Moving Picture Experts Group · 2001

Compression: lossy
Transparency: No

✓ Universal compatibility across all platforms
✓ Excellent compression with H.264/H.265
✗ H.264 has royalty implications

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

MP4 magic bytes: 00 00 00 xx 66 74 79 70

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

Why convert MP4 to AAC?

You recorded a lecture, podcast interview, or live stream as an MP4 video, but all you actually need is the audio. Watching a video just to listen wastes bandwidth, battery, and storage — and many podcast apps, streaming platforms, and audio players won't accept video files at all. The audio track has been sitting inside your MP4 the whole time; this converter pulls it out.

AAC is the right target for this workflow. It's the default audio codec inside every MP4 from iPhone, Android, GoPro, and most cameras — meaning extraction is usually direct and lossless: the existing AAC stream is simply unwrapped from the video container and saved as a standalone file. No re-encoding occurs, and audio quality is identical to what was inside the video. AAC plays natively on every Apple device, Android phone, and modern streaming platform.

The resulting file is typically 5–10× smaller than the MP4. A 1-hour MP4 lecture at 256 kbps AAC audio might be 500 MB total — the extracted AAC will be around 115 MB. It works immediately in iTunes, Apple Music, GarageBand, Audacity, Adobe Audition, and any podcast host that accepts AAC or M4A.

Quality & file size: MP4 to AAC

Typical file sizes: MP4 100–300 MB → AAC 2–5 MB.

Both MP4 and AAC use lossy compression. We transcode at high quality settings (equivalent to AAC's recommended web quality) to minimize generational loss.

Color depth: MP4 supports standard color, AAC supports standard color.

Transparency: MP4 does not support transparency. AAC does not support transparency — transparent areas become solid white.

Frequently asked questions

Privacy: how FormatDrop handles your files

Your MP4files 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.