Audio Joiner (Merge Audio)
Merge several audio files into one track locally in your browser, in any order.
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An audio joiner merges several separate audio files into a single continuous track, played back to back in the order you choose. It is what you reach for to stitch podcast segments together, combine voice memos into one recording, assemble a seamless playlist or mixtape, or rejoin parts of a file you split earlier. Instead of sending listeners a folder of clips, you give them one file.
Frequently asked questions
Are my files uploaded to a server?
Can I join files that are in different formats?
How do I control the order of the tracks?
Will joining reduce the quality?
How many files can I join at once?
Is there a gap or crossfade between tracks?
What output formats are available?
Does it work offline?
About Audio Joiner (Merge Audio)
This tool joins audio entirely inside your browser using a WebAssembly build of FFmpeg. Every file is read from your device, combined locally, and the merged result is returned as a download. Nothing is uploaded, so it is safe for private interviews, drafts or unreleased material. You can reorder the files in the list and remove any you do not want before joining.
Because the files you pick may use different formats, sample rates or channel layouts, the joiner re-encodes everything into one consistent output (MP3, M4A or WAV). Re-encoding is what makes mixing formats reliable, a raw copy-and-append only works when every file is byte-compatible, which is rarely true across different sources. The trade-off is a single, light re-encode pass, which is fast for typical files.
The order in the list is the order in the final track, so arrange the files before joining. If you need only part of a file, trim it first with the Audio Trimmer, then join the pieces. As with all the tools here, the whole process runs locally and privately, with no size limits beyond your device's memory.
Concatenation: the oldest trick in audio
Joining sounds end to end is one of the oldest forms of audio editing, older than computers by decades. In the era of magnetic tape, editors literally cut the tape with a razor blade and joined the pieces with splicing tape, assembling radio programmes, music albums and film soundtracks by hand. The physical join had to be precise: a clumsy splice produced an audible click exactly where two waveforms met at different amplitudes.
Digital audio inherited the same challenge in a new form. When two clips are joined, a sudden jump between the last sample of one and the first sample of the next creates a click or pop. Professional tools hide this with tiny fades at the boundary, while careful editors trim each clip to a zero-crossing, the instant the waveform passes through silence, so the pieces meet cleanly. It is the digital descendant of the tape splicer's craft.
Under the hood, joining compressed files is more involved than it looks, which is why this tool re-encodes. Different files can have different sample rates, channel counts and encoder settings, and simply gluing their compressed data together would produce garbled audio. Decoding everything to a common form and re-encoding once is the reliable modern equivalent of laying every piece of tape onto the same reel before playing it back.