Audio Merger – Merge Audio Files Online

How to merge audio files

1. 1. Upload two or more audio files. Files stay on your device.
2. 2. Arrange them in the desired order with move buttons or drag and drop.
3. 3. Select the output format and quality (for example MP3 bitrate).
4. 4. Click Merge Audio. Processing runs locally in this tab.
5. 5. Preview the result if you want, then download it.

How to use the Audio Merger

After the first files are in the list, use Add more files if you still need tracks. Preview each item with the built-in player. The numbered list is the merge order: first item plays first in the output. When encoding finishes, use Download Audio — the file is built in your browser, not fetched from a server.

Supported audio formats

Input: MP3, WAV, OGG, M4A/AAC, and FLAC when the file can be decoded in your browser. Output: MP3, WAV, OGG, M4A, and FLAC. We do not list formats this tool cannot actually write. Some unusual encodings or damaged files will fail with a plain error rather than a technical dump.

How does the audio merger work?

The page reads each file locally and lists them in order. When you merge, a WebAssembly build of FFmpeg runs in a worker: it decodes every track, aligns sample rate and stereo layout, concatenates the streams in list order, and encodes the format you picked. The first merge in a session loads that engine into the browser; your audio still never leaves the device.

Is my audio uploaded?

No. Merging does not send files to Toolshelf servers, and we do not log filenames or audio contents. Site analytics, when enabled, may record anonymous events such as “tool opened” or “merge completed” without file names, sizes, or payloads. The current files and last merge stay in this browser (IndexedDB) so a refresh does not wipe the session. Use Start Over to clear that local copy. Downloads use a temporary object URL that is revoked when you start over or leave the page.

Audio merger features

• Merge MP3, WAV, OGG, M4A/AAC, and FLAC in the browser
• Upload multiple files and add more later
• Reorder tracks with buttons, keyboard, or drag and drop
• Preview each file before merging
• Export MP3, WAV, OGG, M4A, or FLAC with bitrate where it applies
• Download the result locally — nothing is uploaded
• Works on phones and desktops with no account

Frequently asked questions

How do I merge two audio files?

Upload at least two files, put them in the order you want, choose an output format, click Merge Audio, then preview and download the combined file.

Can I merge MP3 files?

Yes. MP3 is supported for both input and output. You can also mix MP3 with WAV, OGG, M4A, or FLAC when those files decode in the browser engine.

Can I merge different audio formats?

Yes. The merger does not glue files together as raw bytes. It decodes each track, normalizes sample rate and channels, then encodes one sequential file in the format you choose.

Do I need an account to use the Audio Merger?

No. Toolshelf Audio Merger requires no account and no signup. Files are processed in your browser, not on a server.

Are my audio files uploaded?

No. Files are read with the browser File API and merged locally with a WebAssembly audio engine in this tab. Audio is not uploaded to Toolshelf servers. The current queue and last merge can stay in this browser until you click Start Over. Analytics, when enabled, only records anonymous events such as “merge completed” — not filenames or audio contents.

Can I merge multiple audio files?

Yes. You can queue up to 20 files, as long as each file is at most 80.0 MB and the combined size stays within 120 MB.

Does merging reduce audio quality?

It depends on the output you pick. WAV and FLAC are lossless. MP3, OGG, and M4A use the bitrate you select (default 192 kbps for MP3). Re-encoding a lossy file can add some extra compression. Choose WAV if you want to avoid another lossy pass.

Can I use the Audio Merger on mobile?

Yes. The upload area, file list, move up/down controls, and Merge Audio button are designed for touch. Drag-and-drop reordering also works where the browser supports it; the buttons always work.

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