Merge Multiple Audio Files

Combine multiple audio files end-to-end in the order of your choice, with an optional crossfade between tracks for smooth transitions. Accepts WAV and MP3 files (MP3s are automatically decoded before merging).

Example:
Add at least two files. The order below is the merge order.
Different formats between files? They are automatically harmonized (sample rate and mono/stereo aligned to the first file in the list) before merging.

How It Works

This tool concatenates your audio files in the displayed order, first converting them to the same format (sample rate, number of channels, bit depth) so the merge is technically possible. If you enable the inter-track fade, each track gets a slight fade-out before the next one and a slight fade-in at the start, softening the transition instead of a hard cut.

Why is automatic format harmonization necessary?

End-to-end merging only makes sense if all files share exactly the same sample rate and number of channels: otherwise, the result would be distorted (incorrect speed or pitch) or simply rejected by the merge engine. The tool therefore automatically resamples each file to the first file's rate and converts mono files to stereo if the first file is stereo. Only a bit-depth difference (e.g., 16-bit vs. 24-bit) cannot be harmonized automatically and triggers an explicit error.

Does the crossfade make two tracks overlap simultaneously?

No: this is not true overlapping mixing (with both tracks playing simultaneously), but rather a volume fade-out at the end of a track and fade-in at the beginning of the next, which limits hard cuts while keeping a simple, predictable end-to-end merge.

100% local processing: decoding, format harmonization, and merging happen entirely in your browser via WebAssembly — your audio files are never sent to a server.