Do the files need the same sample rate?

No. Every input is decoded through the same audio context, and the browser's decoder resamples each file to that context's rate, so they arrive matching by the time the join runs. The output simply takes the first file's rate.

What happens when a mono file is joined with a stereo one?

The narrower file has its missing channels padded with silence, so it sits in the sequence with an empty second channel rather than being forced into one side. The alternative, duplicating the mono channel, would change the level of that section in the mix.

Is there a crossfade between the parts?

No, they are concatenated exactly, which is what makes the result as long as the sum of its inputs. That is the right behaviour for speech and for parts that were prepared to match, and the wrong one for music that should blend, which is what the crossfade creator is for.

Why is the output always called joined.wav?

Because the tool has no single source name to inherit, having combined several files. Rename the download to whatever the finished recording is called; the WAV itself carries no name of its own.

Does the order I drop the files in matter?

It sets the initial order, but the arrow controls change it afterwards, and the list order is what gets joined. Moving a row up or down is the intended way to arrange the sequence, so dropping order is only a starting point.

Audio Joiner

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Audio Merger

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Batch File Renamer

Rename audio files in batches

Audio Joiner places several files one after another to make a single longer recording, in the order you arrange them. It is the sequencing counterpart to the merger, which layers files instead.

What is Audio Joiner?

Add two or more files, rearrange them with the up and down controls, and join. Everyone is decoded up front and listed with its length and sample rate, so the running total is visible before anything is produced.

The interface and what it reports:

A drop zone that accepts several files at once and keeps adding to the list on later drops.
One row per file showing the basename, the duration and the sample rate, with move-up, move-down and remove controls.
A total line giving the file count and the combined duration.
A join-and-download control that produces the combined WAV, named joined.wav.

Joining is a direct concatenation: each file's samples are copied into one output buffer at a running offset, so the result is exactly as long as the sum of its parts and no crossfade or gap is introduced between them. Two details matter. First, the channels of each input are padded with silence when an input has fewer channels than the widest one, which is what makes a mono file joinable into a stereo sequence without throwing an error or shifting the signal to one side. Second, all inputs are decoded through the same audio context, and the browser's decoder resamples to that context's rate, so every input arrives at a matching rate before the join happens — which is why the output takes the first file's rate and why a mixed set of sources joins without a pitch change. The join itself is arithmetic on sample offsets, so it is sample-exact and repeatable. Concatenation is back-to-back by definition, with no crossfade and no gap inserted, so the last sample of one file is immediately followed by the first sample of the next. Channel mismatch is handled by silence padding: a mono file joined into a stereo sequence receives an empty second channel rather than a duplicated one, which keeps its level and its position in the image unchanged. Every file is decoded in the browser, so the sequence never leaves the device.

What the tool does not do:

No crossfade or gap option, so consecutive files butt together unless they are prepared to match.
No level matching, so a quiet file next to a loud one stays quiet.
No metadata handling: the output is a plain WAV and the sources' tags are not carried over.
Multi-channel files beyond mono and stereo are not a supported target.
Everything is decoded into memory at once, so a large set of long files is bounded by what the browser will hold.
The output name is fixed rather than derived from the inputs.

Use it for the straightforward sequencing jobs: joining a two-part interview, assembling a playlist intro and outro, or putting several takes together in the order they should be heard. When the files should play at the same time rather than in sequence, the merger is the right tool, and when the join should be smoothed rather than butted, the crossfade creator blends the two sides.

How to use Audio Joiner

Drop two or more audio files onto the panel; each is decoded and listed.
Use the arrow controls to set the order the files should play in.
Check the combined duration, then press join and download.
Play the result through and confirm the joins sound as intended.

When to use Audio Joiner vs related tools

Audio Joiner is the sequencing tool, so it suits assembling parts into one recording in a chosen order. Audio Merger plays files at the same time instead, for layering and overdubs, and Crossfade Creator smooths the join rather than butting the two files together. When the joined recording then needs tidying, Audio Trimmer and Audio Slicer handle the ends and the interior.

Privacy & Security

This tool runs entirely in your browser — no data ever leaves your device. There is no server round-trip, no upload, no logging, and no account required. Your input is processed locally using client-side JavaScript and is never stored, transmitted, or accessible to anyone else. When you close the tab, everything disappears.