How to use the Audio Joiner
- Drop your audio clips into the box, or click choose files. You can add more at any time.
- Put them in order with the ↑ ↓ buttons.
- Choose what goes Between clips: nothing, a pause, or a crossfade. Tick Even out the volume if some clips are much quieter.
- Click Join clips, play the result to check it, then click Download.
Crossfade or silence?
- Nothing: each clip starts straight after the last. Best for parts of one recording, like a podcast split into pieces.
- Silence: a short pause between clips. Good for voice notes, lessons and playlists of separate tracks.
- Crossfade: the end of one clip fades out while the next fades in, like a DJ mix. Good for music. A crossfade makes the total a little shorter, because the clips overlap.
Mixing formats
You can join different formats in one go, such as an MP3, an M4A from your phone and the sound from an MP4 video. Each clip is decoded by your browser and converted to the same sample rate before joining. If any clip is stereo, the result is stereo.
Even out the volume
Clips recorded on different devices are often louder or quieter than each other. Even out the volume raises each clip so its loudest moment reaches the same level, which is usually enough to stop sudden jumps in loudness.
Private by design
Your clips are joined in your browser and never uploaded. MP3s are made with LAME, the open-source MP3 encoder, through the lamejs library. To trim a clip first, use the MP3 cutter.
Frequently asked questions
Is there a limit on clips or length?
No fixed limit. Very long results need a lot of memory: about an hour of audio is fine on most computers, less on older phones.
Will joining reduce the quality?
MP3s are re-encoded when you save. At 192 or 320 kbps you won't hear a difference. Choose WAV to avoid any loss.
Can I join the audio from videos?
Yes. Add MP4, MOV or WebM files and only their sound is used.
Are my files uploaded?
No. Everything happens in your browser.