Are my MP4 files uploaded anywhere?

No. This conversion runs entirely inside your browser, so the file never leaves your device. You can confirm it yourself: open the network tab of your browser's developer tools and convert something. You will see the page load, plus the analytics and advertising the site is paid for with — and nothing carrying your file.

Is converting MP4 to AAC free?

Yes. There is no account, no watermark and no limit on how many files you convert — it runs on your own machine, so it costs us nothing to let you. Files up to 100 MB are handled in the browser.

Does converting MP4 to AAC lose quality?

AAC is a compressed format, so some data is discarded. At the default setting the difference is not visible; you can raise the quality setting if you need to be certain. Only the first soundtrack is kept. A film with a second language or a commentary track loses it.

Do I need to install anything to open AAC files?

No installation is needed for the conversion itself — it runs in the browser you already have. Opening the AAC afterwards needs whatever software normally handles Advanced Audio Coding on your device.

MP4toAAC

Convert MP4 to AAC

Up to 100 files at once. Mixed formats are fine.

You can convert MP4 to AAC free and without an account: drop the file above and the AAC is ready to download in a second or two. The conversion happens inside your own browser, so the file is never uploaded — it works on Windows, Mac, Linux, iPhone and Android, and keeps working with the network switched off.

What MP4 and AAC are for

The video format that plays everywhere. If in doubt, this is the answer.

The MP3 successor. Better quality per megabyte, standard on Apple devices and in streaming.

How to convert MP4 to AAC

Drop your MP4 file onto this page, or click to pick one.
Choose AAC as the target. The conversion runs inside your browser — the file is never uploaded.
Download the finished AAC file.

MP4 vs AAC: what changes

MP4 compared with AAC
	MP4	AAC
Full name	MPEG-4 Video	Advanced Audio Coding
File extension	.mp4	.aac
Media type	video/mp4	audio/aac
Compression	Lossy — file size is bought with quality	Lossy — file size is bought with quality

Quality: Some quality is given up for a smaller file. At the default setting the difference is hard to see.
Where it runs: This conversion runs inside your browser. Your file is never uploaded, and it works with the network disconnected.
What can be lost: Only the first soundtrack is kept. A film with a second language or a commentary track loses it.

MP4 to AAC: common questions

Are my MP4 files uploaded anywhere?: No. This conversion runs entirely inside your browser, so the file never leaves your device. You can confirm it yourself: open the network tab of your browser's developer tools and convert something. You will see the page load, plus the analytics and advertising the site is paid for with — and nothing carrying your file.
Is converting MP4 to AAC free?: Yes. There is no account, no watermark and no limit on how many files you convert — it runs on your own machine, so it costs us nothing to let you. Files up to 100 MB are handled in the browser.
Does converting MP4 to AAC lose quality?: AAC is a compressed format, so some data is discarded. At the default setting the difference is not visible; you can raise the quality setting if you need to be certain. Only the first soundtrack is kept. A film with a second language or a commentary track loses it.
Do I need to install anything to open AAC files?: No installation is needed for the conversion itself — it runs in the browser you already have. Opening the AAC afterwards needs whatever software normally handles Advanced Audio Coding on your device.