Add two or more audio files, reorder them, and merge into a single track. Mixed formats and sample rates are handled automatically.
The Audio Merger joins any number of recordings into one continuous file — intro + interview + outro, a set of voice memos, several song sections or an audiobook’s chapters. Files can be of different formats, lengths and even sample rates; the merger resamples mismatched files and upmixes mono to stereo automatically.
Beyond plain concatenation it offers two things most free mergers lack: an equal-power crossfade that blends the end of one file into the start of the next, and loudness matching so a quietly recorded clip does not sound like a drop-out next to a loud one.
Each file is decoded to floating-point samples. If sample rates differ, the lower-rate files are resampled to the highest rate with the browser’s high-quality resampler so none are sped up or slowed down. Channels are matched to the widest file. For a crossfade of x seconds the tail of file n is multiplied by cos(πt/2x) and the head of file n+1 by sin(πt/2x), which keeps perceived loudness constant through the blend.
With Match loudness on, every file is measured with the ITU-R BS.1770-4 gated loudness meter and gained to −16 LUFS (limited to −1 dBTP) before joining.
Stitch intro music, the episode and an outro into one file for hosting.
Combine chapter recordings; add 1–2 seconds of silence between chapters.
Chain tracks with 3–8 second crossfades.
Combine several voice notes into a single shareable file.
| Files | 2 or more, any order, drag to re-order |
|---|---|
| Crossfade | 0–8 s, equal-power |
| Gap | 0–5 s of silence |
| Mixed rates/channels | Automatically resampled / up-mixed |
| Loudness match | −16 LUFS, true-peak limited at −1 dBTP |
No fixed limit — the practical limit is your device’s memory.
Yes. Everything is decoded first, so formats can be mixed freely.
The merged result is encoded once at the end. For zero generation loss choose WAV.
Yes — you can mix MP3, WAV, M4A, OGG and FLAC in the same merge; each is decoded to raw audio before combining.
The merger automatically resamples every file to match the highest sample rate in your list, so there's no pitch or speed mismatch.
No fixed limit — the practical ceiling is your device's available memory.
This tool runs entirely in your browser using the Web Audio API. Nothing is uploaded, stored or shared — there is no server to send your file to, so it works offline once the page has loaded.
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