Merging joins audio files end to end, in the order you upload them, into a single file. It is useful when a recorder split a long session into parts, when you want one file for an audiobook chapter, or when you assemble an intro, interview and outro into an episode.
Do the files need to be the same format?
No. You can mix an MP3 intro, a WAV interview and an M4A outro. Every file is decoded, brought to a common 44.1 kHz stereo format, joined, and then encoded once into the output format you choose. Mono recordings play on both channels.
Which output format should I choose?
MP3, the default, for anything you will publish or share: it is encoded with LAME at variable bitrate quality 2, typically 170 to 210 kbps. WAV or FLAC if you will edit the result further, since both are lossless. M4A or AAC at 192 kbps for Apple devices, and Opus at 128 kbps for the smallest file with good quality.
Does merging reduce quality?
Joining itself does not. The single encode at the end is lossy for MP3, AAC, M4A, OGG and Opus, like any save in those formats, but at these settings it is not audible in normal listening. Files recorded at 48 kHz are resampled to 44.1 kHz, which is the CD standard and loses nothing you can hear.
Is there a gap between tracks?
The files are joined back to back without added silence. Any silence already at the start or end of each file stays, so trim those first with Trim Audio if the joins should be tight.
Is it private?
Merging runs on our server. Your files are uploaded over an encrypted connection, joined in Germany and deleted automatically within two hours.
How big can the file be?
Files up to 50 MB each. Merging up to 5 files is free without an account, and up to 10 with a free account; longer merges, such as a full audiobook, need Pro (up to 500 files) or credits. Each file counts toward the daily allowance of server jobs.
How to merge audio files
- Drop two or more audio files onto the drop zone, in the order they should play.
- Choose the output format.
- Click Merge.
- Download the combined file.
FAQ
Can I add a crossfade between tracks?
No. Files are joined directly, without fades or overlap.
Can I change the order after uploading?
The files are joined in upload order. If they are in the wrong order, remove them and add them again in the right sequence.
Can I merge audio and video?
No. This tool joins audio files only.
Why is my merged file stereo when the recordings were mono?
Everything is brought to stereo so files can be mixed freely. A mono voice simply plays equally on both sides.