1Upload every file you want combined — at least two of them.
2Drag the uploaded items into the order you want; the order is taken from the list, not from the filenames.
3Start the merge, which joins matching inputs without re-encoding them and reconciles mismatched ones exactly once.
4Download the single combined FLAC file.
Merge FLAC FAQ
How does Merge FLAC join the files together?
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Concretely, the PCM streams are joined sample-exactly, so the result is bit-identical to the inputs laid end to end — which is why lossless is the right family to assemble a master in. Upload everything you want combined and the result comes back as a single file.
Can I control the order things are joined in?
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Yes — drag the uploaded items into the order you want before starting. Order is taken from the list, not from the filenames, so "track2.mp3" sorting after "track10.mp3" is not a problem you have to solve first.
Does it matter if the inputs are different formats?
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It does. FLAC is lossless compression — bit-identical to the source on decode, at about half the size of WAV. Matching inputs take a fast, lossless path; mismatched ones have to be reconciled to a common format, which is slower and costs one encode.
Anything specific to FLAC when merging?
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Yes — FLAC decodes bit-identically to the source, so any number of edit-and-resave cycles cost you nothing in fidelity. That is worth checking when the inputs did not all come from the same source.
How many files can I combine at once?
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On the free tier a merge accepts two files at a time, which is deliberately higher than the single-file limit on other tools because merging one file is meaningless. A pass removes the cap entirely.
Is the merge lossless?
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It is whenever the inputs already agree — the encoded data is copied straight through. It stops being lossless only when the inputs disagree and something has to be re-encoded to make them compatible, and even then it is one pass, not one per file.
What can I upload to Merge FLAC?
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WAV, FLAC and AIFF, at any bit depth and sample rate up to and including 24-bit/192 kHz. Lossy files work in the same batch if you are mixing sources.
Is there a file size limit on Merge FLAC?
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Yes: free accounts process audio up to 15 MB per file — for uncompressed PCM that is roughly twenty minutes of CD-quality stereo, so it is a real limit here in a way it is not for MP3. If you are over it, converting WAV to FLAC first is the free fix — it is lossless and roughly halves the size.
Will Merge FLAC lower the quality of my FLAC audio files?
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No. Lossless audio is edited sample-exactly, so what comes back decodes bit-identically to what you would get doing the same edit in a desktop editor. You can repeat the cycle as many times as you like without accumulating any loss at all.
Can I run Merge FLAC on several FLAC audio files at once?
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Yes, though lossless files are large, so the batch is bound by upload bandwidth rather than by processing. Settings apply uniformly across the set.
Are bit depth and sample rate preserved?
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Yes, unless you change them deliberately. A 24-bit/96 kHz source stays 24-bit/96 kHz — nothing is silently downsampled to 16/44.1, which is the failure mode that makes a master unusable.
Does Merge FLAC cost anything?
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No. Merge FLAC is free with no account required, and nothing is added to the audio. Uploads are deleted from the workers shortly after the job finishes.
