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Merge Audio

Join tracks end to end into one continuous file. Some detail is discarded to fit the target format; how much depends on the format and your settings.

Not uploaded to any serverConverted on this deviceGone when you close the tabHow this works

Drop your files here

MP3, WAV, FLAC, AAC and 4 more formats · up to 300 MB each

or paste files from your clipboard

Ready when you are

Join tracks end to end into one continuous file. Everything happens in this tab; nothing is sent anywhere.

⌘K to search converters

How to use it

1
Add your files
Merge Audio works with MP3, WAV, FLAC, AAC, M4A, OGG, Opus and AIFF. Drop them in, browse for them, or paste from your clipboard.
2
Put them in the right order
The files are processed top to bottom. Drag them to rearrange before you start.
3
Run it and download
Press the button and save the result. Everything happens on your device, and nothing is uploaded.

Privacy, in plain words

Is it safe? Your audio file is not uploaded anywhere

What “uploaded” normally means. On most online converters, pressing the button copies your file across the internet onto a computer owned by that website. That copy is what the word “upload” means, and it is the part nobody explains.

What happens instead. This site does not do it. There is no server here that receives files, so your audio file is read, converted and handed back by the browser you are using right now. It never travels — so there is no copy to store, read, leak or hand over.

Check it yourself in ten seconds

Turn off your Wi-Fi after this page has loaded, then convert a file anyway. It still works, because everything needed is already on your device.

The longer explanation of how this works, and the full detail of what is and is not stored on the privacy page.

Why this matters more than it sounds

An audio file is a conversation. Transcribed by machine — which is cheap now — it becomes searchable text about whoever was speaking. It matters more than it sounds, because of what audio files usually are:

Call recordings

both sides of a conversation, often legally sensitive

Interviews

a source's voice is identifying even when the name is not said

Voice notes and dictation

thinking out loud, never meant for an audience

Therapy and consultation recordings

clinical material with strict handling rules

A file that is never sent cannot be kept, leaked, subpoenaed or used to train anything. That is a property of how this works, not a promise about how carefully it is run.

Joining recordings end to end

Merging plays the files one after another in the order you list them and writes the result as a single track. It is concatenation rather than mixing: nothing is layered, and two files do not play at once.

Files that share a format, sample rate and channel count can often be joined without re-encoding, which is lossless and fast. A mixture — a mono voice note and a stereo music track, or a 44.1 kHz file and a 48 kHz one — has to be converted to a common format first, and that pass is lossy.

Levels are not matched: A quiet recording followed by a loud one stays exactly that. Normalising each part first is what makes a joined file listenable.
Order is the interface: Files are joined top to bottom as listed, so arrange them before you start.

Measured, not estimated

What this tool actually does to a file

Joining two copies of the same two-second recording end to end.

The result came out 1.5× larger than the file that went in.

Each row is one document, chosen because this tool behaves differently depending on what is inside the file.
Sample	In	Out	Change
An easy clipThe compressible end of the range — a clean tone, or a moving test pattern — where a codec does its best work.	64.6 KB	96.2 KB	+49%
A hard clipThe other end — pink noise, or dense video grain. Close to incompressible by design, and the worst case for every codec.	64.6 KB	96.2 KB	+49%

Produced by this site's own converter. The same code that runs in your browser, at the same default settings, so these are the bytes you would download.

Samples are generated from a fixed seed rather than taken from real photographs or documents, so the corpus is reproducible and carries no licensing question — and so the numbers predict the shape of your result rather than its exact size. Measured 2026-10-01. The method, and the command that regenerates every figure on this page, are on the how it works page.

About these formats

Accepts

MPEG-1 Audio Layer III

The universal lossy audio format.

Extensions: .mp3
MIME type: audio/mpeg
Best for: Music players · Podcasts · Maximum compatibility
Compatibility: Plays absolutely everywhere.

Accepts

Waveform Audio

Uncompressed PCM audio. Perfect quality, big files.

Extensions: .wav, .wave
MIME type: audio/wav
Best for: Editing and mastering · Sound design · Archival
Compatibility: Universal.

Good to know

Merge Audio — questions

How does Merge Audio work?

Join tracks end to end into one continuous file. Add your files above, adjust anything you want to change, and press the button. The result downloads straight to your device.

Is Merge Audio safe — are my files uploaded to a server?

No, nothing is uploaded. On most online tools, pressing the button copies your file across the internet onto a computer owned by that website, where it is processed and then sent back. That copy is what "upload" means. This tool does not do it: your file is read and processed by the browser you are using right now, stays on this device the whole time, and is discarded when you close the tab. Turn off your Wi-Fi after the page loads and it still works, which is the quickest way to confirm it.

Can I use this on confidential or personal documents?

Yes — that is the case it was built for. Because the file never leaves your device, a confidential document is no more exposed than it is sitting in your own folder: there is no transfer, no copy on anybody else's hardware, no retention period and no staff with access. Nothing about the file is logged either — not its name, not its size, not its contents.