Audio Joiner
Stack your files up and glue them into one.
choose them all at once, you can reorder them after
The player above previews the first file only. The merged result is built when you download.
How to use it
- Drop every file you want to merge onto the page in one go. They are decoded on your machine. Nothing is sent anywhere, and there is no queue to wait in.
- Put them in the order you want. Drag a row by its handle, or use the up and down buttons on each row if you would rather not drag. Row one plays first.
- Set a gap if you want a pause between tracks. Zero joins them with no space at all, which is what you want for segments of one continuous recording.
- Pick an output format and download. The merged file is written from the decoded samples, so the parts line up exactly where the list says they will.
What joining actually does
When two audio files are joined here, nothing clever happens. The samples of the second file are written into memory directly after the last sample of the first, and the result is saved as one file. There is no analysis, no attempt to match keys or tempos, no re-timing. That is why it finishes in about the time it takes to press the button, and it is also why the output is exactly as good as the material you fed in.
The one complication is files that disagree about their format. A 48 kHz stereo export and a 44.1 kHz mono voice memo cannot simply be placed end to end, because their samples do not represent the same slices of time and one of them has half as many channels. Everything is brought to the highest sample rate and the widest channel count present before the join, so the voice memo is resampled upward and copied across both channels. The alternative (matching downward) would quietly degrade your best source to accommodate your worst, and that is the wrong default.
Order, gaps and the seam itself
A join with no gap is a hard edit. If the first file ends mid-waveform at, say, 40 percent of full scale and the next one starts at minus 30 percent, the speaker is asked to make that jump in the space of one sample. Your ear registers it as a tick. Files that were exported properly end on silence and this never comes up; files that were themselves cut out of something bigger very often do.
Gap conventions are worth knowing because they are load-bearing. Roughly two seconds between album tracks reads as deliberate. One to two seconds between audiobook or podcast chapters gives a listener time to register that something changed. Between two halves of a single continuous take, any gap at all sounds like a mistake. Join those at zero and, if there is a click, fix the click rather than papering over it with silence.
One encode, not one per file
Every source is decoded to raw samples first, joined in that raw form, and encoded once at the end. Merging five MP3s therefore does not stack five generations of MP3 damage onto the result. Each input arrives carrying whatever loss it already had, the join adds none, and the export adds exactly one more pass. At 192 kbps or higher that pass is inaudible to almost everyone.
If this merge is one step of several. Say you plan to normalize the result, or trim the front. Take WAV or FLAC out of here instead. Both are lossless, so the intermediate steps cost nothing, and you encode to MP3 once at the very end. FLAC is roughly half the size of WAV for identical audio, which matters when the merged file is an hour long.