Audio Joiner
Concatenate multiple audio files in order, lossless when parameters match
Drag & drop files here
or browse files
Select multiple audio files at once; more can be appended
About this tool
Stitching segmented lecture recordings back into one file, chaining audiobook chapters in order, or stringing songs into a continuous mix - this tool concatenates audio files in the order you arrange them and outputs a single file. Reorder with the arrow buttons, remove strays with the cross, then merge with one click.
Every segment is decoded and re-encoded to the chosen format and bitrate, which guarantees consistent sample rate and channels even when the sources differ - no speed shifts, no clicks at the seams. When all inputs already share the same format and parameters (say, identical stereo MP3s), the tool concatenates the streams losslessly instead, finishing in seconds with zero quality change.
The merging runs on FFmpeg compiled to WebAssembly inside your browser: nothing is uploaded, so private recordings are safe to process.
Features
- Any number of inputs joined in your order, with up/down reordering
- Output as MP3 / WAV / M4A / OGG / FLAC with selectable bitrate
- Automatic lossless concatenation for matching same-format inputs
- Mismatched formats, sample rates and channels are unified safely
- Fully local processing with live progress and cancel
How to use
- Select multiple audio files at once (more can be appended)
- Reorder with the arrows, remove unneeded files
- Pick the output format and bitrate, then click Merge audio
- Audition the result and download
Frequently asked questions
- Can I merge files in different formats?
- Yes. Everything is decoded and re-encoded into one format, which also normalises sample rate and channel count - the usual causes of pitch shifts and clicks at seams. If all inputs already match (identical 44.1 kHz stereo MP3s, for example), lossless stream concatenation kicks in instead and nothing is re-encoded.
- The merged order came out wrong - how do I fix it?
- The order is exactly the list order on the page. Every row has up/down buttons that move it instantly; arrange the list first, then merge. Files numbered 01, 02... in their names are merged in the order you added them - the tool never re-sorts on its own.
- Is there a limit on file count or length?
- No hard count - memory is the ceiling. All segments and the output must fit in browser memory at once, so keep a single job under roughly 500 MB total. For hour-long audiobooks, merge in batches of about an hour at a time.