Merge Audio Files
Processed locally in your browser — nothing is uploaded.
Quick answer
To merge audio files, you concatenate them — the second file starts the instant the first ends, the third after that, and so on, producing one continuous track. This tool joins two or more files in the order you arrange them, in your browser, with nothing uploaded. First use downloads the ~32 MB engine once; after that it is cached, so later merges begin immediately.
How to merge audio files
Add your files
Drop in two or more audio files. Podcast segments, song parts, voice notes — anything you want played back to back.
Set the order
Drag the files into the sequence you want. The track plays top to bottom, so the first item is heard first.
Merge and download
Click merge to join them end to end and download the single combined file.
How does joining files end to end work?
Merging is concatenation: the tool lines your files up nose to tail and writes them as one stream, so there is no overlap and no gap unless you introduce one. It is not mixing — the files do not play at the same time, layered on top of each other. If you want two sources playing simultaneously (a voice over a music bed, for instance) that is mixing, a different operation. Merge is for sequence: part one, then part two, then part three.
Order is the one thing you control that no later step can fix cheaply, so it is worth getting right before you export. The tool plays your list strictly top to bottom, and because the join is a single pass there is no crossfade inserted between items unless you add one — the last sample of one file is immediately followed by the first sample of the next. If you want a beat of silence between segments, add it to the individual files first, then merge.
Do the files need to be the same format?
For a clean, fast join it helps if the files share the same codec, sample rate and channel count — then they can be stitched without re-encoding. When they differ, the tool re-encodes to a common format so the seams line up. That is normal and usually invisible, but it is worth knowing why a mixed batch takes slightly longer than a matched one.
| Situation | What the tool does | Speed |
|---|---|---|
| Same codec, rate & channels | Stream copy, no re-encode | Fastest, lossless |
| Same codec, different rate | Resample to a common rate | Fast |
| Different codecs (MP3 + WAV) | Re-encode to one format | Slower |
| Mono mixed with stereo | Upmix to a common channel layout | Fast |
What is merging good for?
- Assembling a podcast from an intro, the interview and an outro.
- Stitching song stems or movements into one continuous piece.
- Combining chapter-by-chapter audiobook recordings into a single file.
- Joining a run of voice memos into one shareable track.
Are my files uploaded to merge them?
No. All of your files are read into memory and concatenated by ffmpeg.wasm inside your browser tab; the combined file is built locally and offered as a download. Nothing is sent anywhere. Verify it in DevTools → Network: merge a batch and watch — no upload request is made. For unreleased tracks or confidential recordings, that means the raw material never leaves your machine.
Related audio and video tools
The reverse operation is split audio, which cuts one file into two. Want to top and tail a part before merging? Use trim audio. Merged podcast too large to email? Compress the audio afterwards. And if a segment is currently trapped in a video clip, extract the audio from the video first, then bring it in here.
Your files never leave your device
Processed locally in your browser — nothing is uploaded. You can verify it yourself: open your browser’s developer tools, watch the Network tab, and use the tool — no upload request is ever made.
Frequently asked questions
How many files can I merge at once?
As many as fit in your device’s memory — well into the dozens on a typical machine. Add them all, arrange the order, and merge in one pass.
Can I merge an MP3 with a WAV?
Yes. When formats differ the tool re-encodes them to a common output so the join is seamless. Matching formats merge fastest and without re-encoding.
Does merging overlap the files or play them together?
Neither. Files play strictly one after another. Layering two sources at once is mixing, which is a separate operation.
Why is there a click where two clips meet?
Usually a loudness jump or a non-zero waveform at the boundary. Normalise the parts first, or add a brief fade at the seams, and the pop disappears.
What order will the files play in?
The order you arrange them, top to bottom. Drag to reorder before you merge.
What format is the merged file?
If all inputs share a format, the output keeps it. If they differ, the tool encodes the result to a single common format.
Is anything uploaded?
No. The merge runs entirely in your browser via WebAssembly. You can confirm there is no upload in the Network tab of your developer tools.