Convert AAC to FLAC online

Your AAC file is converted to FLAC right here in your browser, using FFmpeg compiled to WebAssembly. Nothing is uploaded to us, the audio never leaves your device. Quality is preserved and the download is ready in seconds.

What is an AAC file?

AAC (Advanced Audio Coding) is MP3's designed successor: at the same bitrate it preserves noticeably more detail, especially at the low bitrates where MP3 falls apart. It is the audio inside YouTube videos, M4A files and most streaming services.

AAC is everywhere modern media is: YouTube, iPhones, Android, streaming platforms. Raw .aac files are less common than AAC-inside-M4A, but they behave the same.

Why FLAC?

FLAC (Free Lossless Audio Codec) compresses audio the way ZIP compresses files: the data gets smaller (typically 50 to 60% of WAV size) but decodes back to exactly the original samples. Nothing is lost, ever.

Convert to FLAC to archive: you keep bit-perfect quality at roughly half the size of WAV, with full metadata and checksum support built in. It is the right long-term home for irreplaceable recordings. The rare weak spot is legacy hardware: very old players and some embedded systems only understand MP3 or WAV.

Frequently asked questions

Will converting AAC to FLAC lose quality?

Honest answer: quality stays exactly where it is, no better, no worse. FLAC is lossless, but it cannot restore detail your AAC already discarded when it was first encoded. What you gain is safety: the FLAC copy can be edited and re-exported repeatedly without any further loss, which is exactly why editors ask for it.

Is it free?

Yes, completely, with no account and no watermark. The conversion runs on your own device, so it costs us nothing to let you use it. The only limit is file size: up to 50 MB, which is what a browser can hold in memory comfortably.

Do I need to install anything, or upload my file?

Neither. It runs entirely in your browser using FFmpeg compiled to WebAssembly. Your audio is never sent to us, which is also why it works on a slow connection, only the page downloads, not your file.

Need a transcript of the audio?

Autrans also transcribes audio in Nigerian English, Pidgin, Yoruba, Hausa, Igbo, French, and Spanish.