Audio Joiner
Choose two or more files, put them in order, pick a gap or a crossfade and export one WAV. It runs in your browser, joins up to 20 files, and nothing is sent anywhere.
Use audio you made or have permission to use. Nothing is sent anywhere, so we never hear or keep it.
Joined. Melodious can turn the finished track into a music video — See the music video maker
Eight worked examples
Each case is the tool's own arithmetic run on tracks at 44,100 Hz. The numbers are what the widget above would show for files of the same lengths and the same settings.
Three tracks of 3:00, 3:20 and 2:30, straight on
- Joined: 8:50.000 (23,373,000 frames), 89.2 MB
- Channels: stereo
The same three with a 2-second gap between
- Joined: 8:54.000 (23,549,400 frames), 89.8 MB
- Channels: stereo
- Silence between files: 2.00 s
The same three with a 3-second crossfade
- Joined: 8:44.000 (23,108,400 frames), 88.2 MB
- Channels: stereo
- Overlap at each join: 3.00 s
A crossfade longer than the shortest file allows is shortened
- Joined: 3:02.000 (8,026,200 frames), 30.6 MB
- Channels: stereo
- Overlap at each join: 2.00 s
- The crossfade was shortened to 2000 ms because your shortest file is only 4.00 s long.
A mono voice memo joined to a stereo track
- Joined: 3:50.000 (10,143,000 frames), 38.7 MB
- Channels: stereo
- A mono file was copied to both sides so it matches the stereo files.
Two ten-minute tracks are refused, not attempted
- Refused: That WAV would be 201.9 MB. The limit is 100.0 MB, because the file is built in your browser's memory. Choose a shorter part.
One file is not a join
- Refused: Add at least two files to join.
Too many files are refused
- Refused: This tool joins up to 20 files at a time.
A crossfade overlaps the end of one file with the start of the next, so the result is shorter than the sum of the files by that overlap at each join. A gap adds silence, so it is longer.
How to join audio files
Choose your files all at once, or drop them onto the box, and add more later if you forgot one. Each appears in a list with its name, length and whether it is mono or stereo. The order of the list is the order of the result. Use Up and Down on a row to move it, and Remove to drop it. Every button has a name a screen reader can read, so the whole job works without a mouse.
Then choose what goes between the files and press Play the result to hear the whole thing, joins included. The readout above the buttons gives the exact length, frame count and file size before you export. The export writes one WAV and downloads it.
Straight, with a gap, or with a crossfade
Nothing between the files is the plainest join: the last sample of one is followed by the first sample of the next. It is exact, and it is right for files that were cut from one recording and belong together, such as the parts of a long voice take.
A gap puts silence between files, from a fraction of a second up to ten, and it is what you want for a set of separate songs or a run of spoken clips. A crossfade overlaps the files instead, fading one out while the next fades in with an equal-power curve, which keeps the level steady through the join. It is the choice for two pieces of music that should flow together, and it always shortens the result by the overlap at each join.
Mixed formats, mixed rates, mixed channels
The files in a list do not need to match. Your browser opens each one with its own decoder, so MP3, WAV, M4A, FLAC and OGG can sit in one list. They are all decoded at one sample rate, that of the first file, so that they can be laid end to end without any one of them playing too fast or too slow. A file recorded at another rate is resampled by your browser, which is accurate but not perfect.
Channels are matched the same way. If any file is stereo the result is stereo, and a mono file is copied to both sides. The page notes when it has done so. If the order matters for the rate, put the file you most want to keep unchanged at the top of the list.
Limits, stated up front
The tool joins up to 20 files. Each can be up to 150 MB and 15 minutes, and the finished WAV can be up to 100 MB. The reason is memory: every file is held decoded in your browser while you work, which takes many times the size of an MP3, and the joined copy is built in memory before it is saved. A file that would push the total over the limit is left out, and the message names it.
It writes a 16-bit WAV, so the result is larger than the MP3s it was made from. It does not match the loudness of the files to each other, so a quiet file next to a loud one stays quiet; the volume booster can bring them closer first. It does not change the pitch or speed of anything.
Before and after you join
If a file has dead air at the start or a mistake in the middle, trim it first with the audio cutter. If two files are at different levels, set each with the volume booster before they go in the list. The reverse audio page can flip a clip you want to place before its forward version.
To repeat one piece of a joined file as a bed, the audio loop maker repeats a region, and the BPM finder reads the tempo of the result. To put the joined track under a picture, the MP3 to video page makes a video file.
From a joined track to a finished video
A single joined file is easier to build a video around than five separate ones. For the wider route, the guide to making a music video for your song covers it end to end.
When the finished track should have scenes, a character and a story, the AI music video generator storyboards it and renders it to your audio. It is paid, from $19/month, and you see the cost before anything renders. The WAV you make here stays on your device unless you upload it yourself.
Frequently asked questions
How do I merge audio files into one?
Choose two or more files at once, or drop them onto the box. They appear in a list in the order you added them. Use Up and Down to change the order, pick what goes between them, and press Join and export WAV. The result is one file with the first on the list at the start.
Can I join an MP3 and a WAV together?
Yes. Every file is opened by your browser's own decoder, whatever format it was, and the joined result is a WAV. A list can hold MP3, WAV, M4A, FLAC and OGG files together, as long as your browser can open each one on its own. A file that does not open is named in the message and the rest still join.
What happens if the files have different sample rates?
Every file is decoded at the sample rate of the first one on the list, and your browser resamples any file recorded at another rate to match. The widget shows the rate in use and the WAV is written at it. Put the file with the rate you care about first, and expect a tiny loss of top-end detail in a file that had to be resampled.
What is the difference between a gap and a crossfade?
A gap inserts silence between two files, which lengthens the result and is right for separate songs or spoken clips. A crossfade overlaps the end of one file with the start of the next while the first fades out and the second fades in, which shortens the result by the overlap and suits two pieces of music that should run into each other.
Why is the crossfade shorter than the one I asked for?
A crossfade cannot be longer than half of your shortest file, because a file in the middle of the list fades in at one end and out at the other, and the two overlaps must not collide. When that limit applies, the page shortens the crossfade, states the length it used and shows the new total.
How does it join a mono file to a stereo one?
The mono file is copied to both sides, so it sits in the middle of the picture and plays at the same level it had. The joined file is stereo whenever any file in the list is stereo, and the page says when it has done this. Nothing is lost from the stereo files.
How many files can I join, and how long can the result be?
Up to 20 files, each up to 150 MB and 15 minutes, with a combined result that stays under 100 MB as a WAV, about 9.9 minutes of stereo at 44,100 Hz. A file that would push the total past the limit is not added, and the message says so. Gaps are limited to 10 seconds and crossfades to 5.
Is the joined file one continuous recording?
It is one file, written in a single pass from the samples of each input in order. With nothing between the files the join is sample to sample, which is exact but can click if the waveform is at a different level on each side. A short crossfade removes that click. Gapless albums are a good case for a crossfade of a few milliseconds.
Does the joiner upload my files?
No. Each file is read by your browser, joined by code running in your browser and saved back to your device. The page makes no request with any of your audio, there is no upload step and no account, and the code that does the joining contains no network call. Closing the tab clears everything.
Can I join tracks that belong to someone else?
Only with permission. Use audio you made or have permission to use. A mix made of other people's recordings and posted publicly can infringe their copyright, whatever the tool does to it, and the page cannot tell whose audio a file holds, so the check is yours.
One file, one song, one video
Attach the joined track and describe the look. An AI director storyboards it scene by scene and renders it to your audio. Plans from $19/month, and you see the cost before anything renders.
Start your videoMore tools: Audio cutter · Reverse audio · Volume booster · Audio loop maker · MP3 to video · BPM finder