How to Join Audio Files Online (Free, No Upload)

To join audio files online, drop your separate files into a browser-based [audio joiner](/join-audio), arrange them in the order you want them to play, choose an output format, and export a single combined file. PixelTools' Audio Joiner runs entirely in your browser using WebAssembly (ffmpeg.wasm), so none of your files are uploaded to a server — nothing leaves your device. It accepts up to 20 files at once in MP3, WAV, M4A, OGG, or FLAC, and lets you pick which of those formats the merged file comes out as, defaulting to MP3. It's the reverse of a splitter: many input files become one output file.

Joining audio comes up any time separate recordings actually belong together as one piece. Voice memos recorded in several short takes need to become one continuous file instead of a scattered list of clips. Podcast segments recorded separately — an intro, an interview, an outro — need to be combined into a single episode file before publishing. Multiple song files ripped or downloaded separately sometimes need to be merged into one continuous track, for example for a mix or a side of an album. Meeting or lecture recordings split across several files because of a recorder's time limit need to be stitched back into one recording so they're easier to review or share. In each case, the goal is the same: turn several files into a single one, in a specific order, without re-recording anything.

Open [Audio Joiner](/join-audio) and add the files you want to combine — up to 20 at once, in any mix of MP3, WAV, M4A, OGG, or FLAC. Arrange them in the order you want them to play in the final file; the joiner outputs them one after another in that sequence. Choose an output format from the same list — MP3 is the default, but you can pick WAV, M4A, OGG, or FLAC instead if that suits your use case better. Export, and the tool combines everything into a single file. Because the merging happens with WebAssembly directly in your browser, there's no upload wait and no server queue — processing runs on your own device.

The order you arrange files in before exporting is what determines the order they play in the final combined file, so it's worth double-checking the sequence before you export rather than after. Audio Joiner also doesn't require every input file to already be in the same format — you can combine an MP3 voice memo with a WAV recording and an M4A clip in a single job, since the tool decodes each one and encodes them together into whichever output format you choose. That output format doesn't have to match any of the inputs either; picking MP3 for a smaller file, or WAV or FLAC for lossless quality, is a separate choice from what formats you started with.

These three tools solve related but distinct problems, and it helps to know which one matches your task. [Audio Trimmer](/trim-audio) takes one file and cuts it down to a single start/end range — one input, one shorter output. [Audio Splitter](/audio-splitter) takes one file and divides it into multiple output files — one input, many outputs. Audio Joiner does the reverse of the splitter: it takes multiple separate files and combines them, in the order you set, into a single output file — many inputs, one output. If you're starting with several files and want one, use the joiner. If you're starting with one file and want several, use the splitter. If you just need less of one file, use the trimmer.

Audio Joiner runs fully client-side in the browser using WebAssembly (ffmpeg.wasm) — the same approach used across PixelTools' audio tools. Your files are decoded, combined, and re-encoded on your own device; none of them are uploaded to a server, which matters when the recordings are personal, unreleased, or otherwise not something you want passing through a third party. There's no account required and nothing to clean up afterward, since the files were never stored anywhere but your own machine. The tool accepts MP3, WAV, M4A, OGG, and FLAC as input, up to 20 files per job, and lets you choose any of those same formats — MP3 by default — for the combined output.

Joining is often one step in a larger audio workflow. If you actually need to go the other way — turning one long file into several separate ones — [Audio Splitter](/audio-splitter) divides a recording into parts. If you only need to keep one section of a file rather than combine several, [Audio Trimmer](/trim-audio) cuts a single start/end range. If your combined file ends up too large to share or upload, [Audio Compressor](/compress-audio) reduces its size afterward. And if any of your source files or the final output need to be in a different format than what Audio Joiner directly offers, [Convert Audio Format](/convert-audio) handles that conversion separately, also entirely in the browser.