How to join audio files
- Choose two or more files. You can select several at once and mix formats freely.
- Put them in order with the up and down arrows. Remove any you do not want, or add more: new files go to the end of the list.
- Choose whether to crossfade between files, and the format to save.
- Press Join and save the result.
The list shows each file's size and length, and the total length once every file has been read.
Crossfade or straight join
With No gap, no fade, each file starts the instant the previous one ends. That is right for parts of the same recording, such as a talk you recorded in pieces, or chapters of a reading.
A crossfade of 1, 2, 3 or 5 seconds overlaps the end of one file with the start of the next, one fading out as the other fades in. That suits songs, where a sudden jump between tracks sounds jarring. Each crossfade overlaps the files, so the joined result is a little shorter than all the files added together. A crossfade is never longer than half of the shortest file; if you ask for more, it is shortened automatically.
What happens to each file
- Every file is converted to 44.1 kHz stereo, the CD standard, so that files with different settings can be joined. A mono voice recording plays equally in both ears.
- The joined result is encoded once, as MP3 or M4A at 128 to 320 kbps, or as uncompressed WAV.
- Volume levels are not changed, so a quiet file stays quiet.
- Song tags such as titles and artists are not copied, since the result is a new, combined file.
- Your original files are never changed.
Ideas for using it
- A medley of song clips for a school function, a wedding sangeet or a dance performance: cut each clip with the audio cutter first, then join them here with a short crossfade.
- Several voice notes or recordings made in parts, joined into one file to send or transcribe. Record new parts with the voice recorder.
- An intro and outro added to a podcast episode or a class recording.
- Sound taken from videos with video to MP3, put together into one track.
Need the result in another format later? The audio converter handles MP3, M4A, WAV, OGG and FLAC.
The engine behind this tool
Video and sound are processed by FFmpeg, the open-source engine behind most of the world's video software, compiled to run inside your browser as ffmpeg.wasm. It is downloaded from this site (about 31 MB) the first time you use a video or audio tool, and your browser keeps it for next time. FFmpeg and ffmpeg.wasm are free software, licensed under the GNU General Public License version 2 or later; their source code is at github.com/ffmpegwasm/ffmpeg.wasm.