Audio Joiner - Online Concatenate Multiple Files

An audio joiner is a tool that concatenates multiple audio files into a single continuous track. This tool processes everything locally in your browser using the Web Audio API — your files are never uploaded to any server. You simply upload your audio files, arrange them in the desired order, optionally apply a crossfade transition, and download the merged result.

We support MP3, WAV, OGG, M4A, AAC, FLAC, WebM, AIFF, WMA, and Opus files. You can even mix different formats — for example, merge an MP3 with a WAV file seamlessly. The output can be downloaded as WAV (lossless, CD-quality) or WebM (compressed, smaller file size).

No files are ever uploaded. All audio processing happens entirely on your device using your browser's built-in audio engine. This means your files remain private and secure. There is also no file size limit imposed by any server — the only limits are your device's available memory and processing power.

Crossfade creates a smooth transition between adjacent audio clips by fading out the end of one clip while fading in the beginning of the next. This eliminates abrupt cuts and makes the merged audio sound like a seamless, professional mix. You can choose crossfade durations from 1 to 10 seconds. Set it to "No crossfade" for a simple concatenation without overlapping.

Yes! You can drag and drop files in the list to rearrange them (on desktop), or use the up/down arrow buttons next to each file to change the order. The files will be merged in the exact order shown in the list, from top to bottom. You can also preview any individual file before merging by clicking the play button.

WAV is an uncompressed, lossless format — it preserves the original audio quality perfectly and renders very quickly (near-instant for most files). However, WAV files are larger (about 10 MB per minute for stereo CD-quality). WebM uses compression to create smaller files, but it requires real-time recording (1× playback speed) and may have slight quality loss. Choose WAV for quality and speed, WebM for smaller file sizes with short audio clips.

Absolutely! This tool is fully responsive and works on iOS and Android devices. You can select audio files from your phone's storage, reorder them using the arrow buttons, and merge them directly in your mobile browser. For large files, we recommend using WAV output for faster processing on mobile devices.