Convert MP4 to AAC online in seconds — free, with no sign-up. AAC is lossy and ideal for the Apple ecosystem and high-quality streaming. Your files are encrypted and deleted automatically after 24 hours.
MP4
MPEG-4 (H.264) — The universal video container — plays on virtually every device, browser and platform.
AAC
Advanced Audio Coding — A modern lossy codec that sounds better than MP3 at the same bitrate; Apple's default.
How to convert MP4 to AAC
- 1Upload your MP4 file
Click “Choose a file” or drag and drop your MP4 file onto the page — no sign-up or email needed.
- 2Convert to AAC
AAC is already selected as the output. Open Options to fine-tune quality if you like, then click Convert.
- 3Download your AAC file
Your AAC file is ready in seconds — click Download to save it. Files are automatically deleted after 24 hours.
MP4 vs AAC
| MP4 | AAC | |
|---|---|---|
| Full name | MPEG-4 (H.264) | Advanced Audio Coding |
| Type | Video | Audio |
| Compression | Lossy | Lossy |
| Best for | sharing and publishing video anywhere | the Apple ecosystem and high-quality streaming |
Frequently asked questions
Does converting MP4 to AAC lose quality?
Both MP4 and AAC use compression, so re-encoding discards a little more data. For a single conversion the change is imperceptible to the ear; just avoid repeatedly re-converting the same file.
What's the difference between MP4 and AAC?
MPEG-4 (H.264) (MP4) is lossy and best for sharing and publishing video anywhere. Advanced Audio Coding (AAC) is lossy and best for the Apple ecosystem and high-quality streaming. Convert MP4 to AAC when you need a audio for the Apple ecosystem and high-quality streaming.
Is the MP4 to AAC converter free?
Yes — converting MP4 to AAC is completely free. There's no watermark, no sign-up and no email required, and you can convert as many files as you like.
Are my MP4 files private and secure?
Yes. Your uploads are encrypted in transit, processed privately, and automatically deleted within 24 hours. We never share, sell or look at your files.
Can I convert MP4 to AAC on iPhone, Android, Mac or Windows?
Yes. The converter runs entirely in your browser, so it works on any device — iPhone, iPad, Android, Mac, Windows or Linux — with nothing to download or install.
How long does it take to convert MP4 to AAC?
Most files convert in a few seconds. Larger files take a little longer, and your upload speed is usually the limiting factor. There's no queue and no waiting for an email.
What else can I convert MP4 files to?
Besides AAC, you can convert MP4 to AVI, FLAC, FLV, GIF, JPG, M4A and more — see the full list of MP4 conversions below.
Other conversions
Last updated July 2026