Step 1: Drop your MP4 files using the button above or by deposit and leave.
Step 2: Click the 'Convert' button to start the conversion.
Step 3: Receive your converted AAC files.
MP4 to AAC Conversion FAQ
Is the MP4 to AAC converter free?
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Yes. One conversion an hour is free, with no account needed, for a file within the free size limit. A paid plan removes the hourly limit and the size limit, and lets you add several files to one job.
Is converting MP4 to AAC a second round of lossy compression?
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Yes, and it is worth planning around. Both formats are lossy, so the AAC encoder is working from audio that has already been through one psychoacoustic pass, and its own decisions compound the first set. At 192 kbps or above the result is still transparent for most listening. If you have a lossless master anywhere, encoding the AAC from that instead avoids the double pass entirely. Almost every MP4 in the wild is H.264 video with AAC audio; the container also legally holds HEVC, AV1 and VP9. AAC is lossy but more efficient than MP3, and it handles up to 48 channels natively rather than being bolted onto a stereo design.
Can I tag the AAC with artist and album information?
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Yes, and it is a genuine gain over MP4, which has nowhere dependable to store any of it. AAC carries title, artist, album, year, track number and embedded cover art in the container itself, so a music library files it correctly without a manual pass. AAC sounds noticeably better than MP3 below 128 kbps and is the default audio track in MP4, YouTube, Apple Music and broadcast.
How big an MP4 file can I convert to AAC?
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Free conversions have a size limit per file, set by the type of file, and the page tells you when a file is over it. A paid plan removes that limit, so much larger files can be converted.
Can I convert many MP4 files to AAC at once?
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Several files in one job need a paid plan. Free use is one file per conversion, one conversion an hour. On a paid plan you can add several files to one job, then download each result on its own or all of them in one ZIP.
Does the MP4 to AAC converter work on phones and tablets?
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Yes — the UI is responsive and the conversion pipeline runs server-side, so mobile devices upload-then-download just like desktops. iOS and Android browser file pickers (camera roll, Files app) work end-to-end.
Which browsers does the MP4 to AAC converter support?
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Chrome, Firefox, Safari (15+), Edge, and Opera. The converter uses standard `<input type="file">` upload — no WebAssembly or PWA dependencies — so even older browsers work.
Are my MP4 files kept private?
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Yes. Uploaded MP4 files are processed on our own servers and are never viewed or shared. Uploads and results are deleted automatically about 24 hours after conversion. See /privacy/ for the full policy.
What if the AAC download doesn't start automatically?
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Disable any pop-up blocker, then click the download button manually. The result link stays active for 24 hours, so if your network fails mid-download, you can re-trigger from the result page without re-uploading the MP4.
How long does MP4 to AAC conversion take?
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It depends on the size and length of the file. Small documents and images are usually ready quickly. Long videos take the longest, because most video conversions re-encode every frame.
