Audio Merger
Join several tracks into a single file — right in your browser.
Runs 100% in your browser — nothing is ever uploaded.
What is Merge?
Merge multiple audio files into one, in order, with optional crossfade. Runs 100% in your browser — free and private. Upload an audio file, tune the settings, preview the result and download it as a WAV file. No installation, no account and no upload: the whole process happens client-side in your browser, which keeps your data 100% private.
How to use Merge
- Open Merge — it supports MP3, WAV, OGG, M4A and FLAC.
- Upload your audio file; it is decoded locally in your browser.
- Tune the settings, then click Process to render the result.
- Preview the output and download it as a WAV file.
Frequently asked questions
What happens if my files have different sample rates or channel counts?
They are resampled and matched automatically before joining, so a 44.1 kHz stereo file and a 48 kHz mono file merge without error. Resampling is high quality but not free — for the cleanest result, use sources that already share a sample rate. Mono files placed in a stereo merge are duplicated to both channels rather than left silent on one side.
How long a crossfade should I use?
For spoken word, 50–150 ms is enough to hide the seam without swallowing words. For music, 1–3 seconds lets the tail of one track breathe into the next. Crossfading overlaps the two regions, so the total duration is shorter than the sum of the parts by the fade length — worth remembering when you are targeting an exact runtime.
Is there a limit to how many files I can merge?
There is no fixed count, but all audio is held uncompressed in memory while it renders. Raw stereo audio costs roughly 10 MB per minute, so an hour-long merge needs well over half a gigabyte and will fail on a phone long before it fails on a laptop. If a long merge stalls, join it in two or three passes instead.
Are my audio files uploaded?
Never. Your file is decoded and processed with the Web Audio API directly in your browser. It never touches a server — processing even works offline.
What formats can I upload and download?
Upload anything your browser can play: MP3, WAV, OGG, M4A/AAC and FLAC in most browsers. The processed result downloads as a high-quality WAV file.
Is it really free? Any length limit?
Completely free with no watermark. There is no hard length limit — a typical 3-5 minute song processes in seconds; very long files just need more memory.