1Upload every file you want combined — at least two of them.
2Add the files in the order you want them joined; the first file you add comes first.
3Start the merge; the files are joined one after another into a single file.
4Download the single combined Audio file.
Merge Audio FAQ
Anything specific to Audio when merging?
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Yes — the codec is detected from the stream, so a mislabelled extension does not derail the job. That is worth checking when the inputs did not all come from the same source.
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.
How does Merge Audio join the files together?
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Concretely, matching inputs are concatenated by copying encoded frames and mismatched ones are normalised once, so the join is as cheap as the source material allows. Upload everything you want combined and the result comes back as a single file.
Does Merge Audio cost anything?
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No. Merge Audio is free without an account, and nothing is added to the audio. The upload and the result are deleted automatically about 24 hours after the job, which leaves time to download the result.
Which audio formats does Merge Audio accept?
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MP3, WAV, AAC, M4A, FLAC, OGG, Opus, WMA and AIFF. Codecs are detected from the stream rather than the extension, so a mislabelled file still works and a mixed batch is handled per file.
Is there a file size limit on Merge Audio?
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Yes: free accounts process audio up to 15 MB per file whichever codec you brought; ffmpeg handles the decode and encode. In practice that limit only bites on uncompressed WAV; a compressed file of the same length is nowhere near it.
Why does a MP3 site host Merge Audio?
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MP3.to is built around the format that made portable audio ordinary: universally playable, small enough to ignore, and lossy in a way that only matters if you keep re-encoding it. Audio jobs cluster: the same person who needs a format changed usually needs the file cut, levelled or made smaller in the same sitting. Putting Merge Audio behind the same upload, the same caps and the same account is what turns three tabs into one.
What should I do with the result once Merge Audio is finished?
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The converter on this site moves audio between MP3, WAV, FLAC, M4A, OGG and Opus, so the output format is a decision you can leave until the end rather than commit to at the start. Doing that after Merge Audio rather than before means the encode happens once, on the file you actually settled on, instead of twice.
Is Merge Audio here the same tool the sibling sites run?
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The engines are shared — the same ffmpeg build, the same workers, the same limits. What a MP3 site adds is a point of view about bitrates, about what survives an encode and about when a lossless intermediate is worth the upload time. It also starts from one fact about the format this site is named after: MP3 frames are fixed-size blocks, so a cut lands on a frame boundary and gapless playback markers do not survive a re-encode.
Do I need an account, and does anything get kept?
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No account is needed. Uploads and results are kept for about 24 hours, which leaves time to download the result, and are then deleted automatically; nobody reads, lists or indexes them. Several files in one job need a paid plan.
