2Drag the start and end handles on the waveform or the timeline, or type exact timecodes if you already know them.
3Preview the selection and run the cut — the part you keep is copied through untouched wherever the format allows it.
4Download the trimmed AAC file.
AAC Cutter FAQ
Is the part I keep re-encoded?
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Not if the format allows a stream copy — the data you keep is bit-identical to the source and the job finishes in about the time the upload took. Only a frame-exact cut on a format that cannot do it cheaply needs a re-encode.
How does AAC Cutter cut the file?
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Concretely, the cut is made on frame boundaries and the surviving frames are copied through without re-encoding, so the audio you keep is bit-identical to the original — no second generation, and the job finishes in about the time it takes to upload. You set the start and end points on the waveform or the timeline and keep what is between them.
Anything specific to AAC when trimming?
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Yes — AAC carries encoder delay in the container, so a naive cut can leave a few milliseconds of silence that a proper trim removes. It explains most of the "the cut is a fraction of a second off" surprises.
Can I remove a section from the middle instead of keeping one?
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Yes — cut the piece before it and the piece after it, then merge the two results. That is deliberately two steps because it keeps both halves on the fast, lossless path instead of forcing a full re-encode.
What can I upload to AAC Cutter?
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MP3, AAC, M4A, OGG, Opus and WMA are the lossy codecs handled directly, and lossless sources (WAV, FLAC, AIFF) can go in the same batch. The codec is probed from the stream, so an incorrectly named file still works.
Is there a file size limit on AAC Cutter?
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Yes: free accounts process audio up to 200 MB per file, which at typical bitrates is several hours of material; ffmpeg does the decoding and encoding, exactly as it would on a desktop. That is the most generous cap on the site after video, and audio work rarely runs into it.
Will AAC Cutter lower the quality of my AAC audio files?
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A lossy file has already discarded detail once, and re-encoding discards more — that is generation loss and it does not undo. Wherever the job can be completed by copying the encoded stream rather than re-encoding it, that is what happens, and the audio comes back bit-identical.
Can I run AAC Cutter on several AAC audio files at once?
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Yes. Upload the set and they process in parallel with the same settings, which is the practical way to handle a podcast series or an album rather than repeating the job by hand.
Why does a EPUB site host AAC Cutter?
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EPUB.to is built around the open eBook format — XHTML in a zip, reflowable by design, and readable on hardware nobody has thought about the layout for. A book is a zip full of markup, images and fonts, so almost every job people bring to an eBook site is really a job on one of those things. AAC Cutter runs on the same upload and the same account as the conversions because that is where it is needed.
What should I do with the result once AAC Cutter is finished?
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The converter on this site moves books between EPUB, MOBI, AZW3, PDF and DOCX, so a title ends up on whatever hardware is actually going to read it. Doing that after AAC Cutter means the conversion is made from the version you settled on, not from the one you were still fixing.
Is AAC Cutter here the same tool the sibling sites run?
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The engines are shared — the same toolchain, the same workers, the same limits. What a EPUB site adds is a view on reflow: which of these operations a reflowable book genuinely supports, and which ones only make sense on the fixed-layout media inside it. It also starts from one fact about the format this site is named after: the book is a zip of XHTML with a manifest, so the text costs almost nothing and every decision that matters is about the embedded images and font subsets.
Do I need an account, and does anything get kept?
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No account, and nothing is kept: uploads are deleted from the workers shortly after the job finishes, nothing is read and nothing is indexed. Free accounts exist for history and batch size, not for access.
