Why is the first run slower?

This tool needs a processing engine that is downloaded once and then cached: ffmpeg.wasm: about 30 MB, fetched once from the jsDelivr CDN and cached by your browser. Only the engine is downloaded. Your file never leaves your device.

Are my files uploaded?

No. This tool runs entirely in your browser tab. Files are read from your disk into memory and the result is generated locally.

Is it free? Are there limits or watermarks?

Free and open source (MIT). There are no file-size caps, daily quotas, accounts or watermarks.

Does it work offline?

Yes, once the page (and any engine it needs) has loaded, it keeps working without a connection thanks to the service worker cache.

Home / Audio / Audio Merger

Audio Merger

Join multiple audio files into one track.

Free, no uploads, no sign-up. Runs 100% in your browser.

How Audio Merger works

Audio Merger runs entirely in your browser. Join multiple audio files into one track. Under the hood it uses ffmpeg.wasm (the FFmpeg media toolkit compiled to WebAssembly (single-threaded core)) and Web Audio API (decodes, mixes and analyses audio for waveforms). Your files are read into this tab’s memory, processed on your own CPU, and handed back to you as a download. Nothing is sent to a server.

Input: MP3, WAV, OGG, AAC, FLAC, M4A.

How to use Audio Merger

Drop an audio file onto Audio Merger (or start recording).
Adjust the options and preview playback.
Process the audio.
Download in the format you picked.

Tips

WAV is lossless but large; MP3/AAC/OGG are compact for sharing.
Engines load on first use and are cached afterwards.

Audio Merger FAQ

Why is the first run slower?: This tool needs a processing engine that is downloaded once and then cached: ffmpeg.wasm: about 30 MB, fetched once from the jsDelivr CDN and cached by your browser. Only the engine is downloaded. Your file never leaves your device.
Are my files uploaded?: No. This tool runs entirely in your browser tab. Files are read from your disk into memory and the result is generated locally.
Is it free? Are there limits or watermarks?: Free and open source (MIT). There are no file-size caps, daily quotas, accounts or watermarks.
Does it work offline?: Yes, once the page (and any engine it needs) has loaded, it keeps working without a connection thanks to the service worker cache.

Related tools

Audio Editor & Trimmer: Trim, fade in/out, change volume and export with a waveform.
Volume Booster and Normalizer: Make quiet audio or video louder, or even out loudness to a standard level (EBU R128).
Audio Converter: Convert MP3, WAV, OGG, AAC, FLAC and M4A.
Voice Recorder: Record your voice with live waveform and export.