Online Audio Joiner – Merge Audio Files Free
About this audio joiner
A free online audio joiner that keeps your files on your device
This online audio joiner puts MP3 and WAV files together into a single file, and it does all of it inside your browser. Ten three‑minute songs at 128 kbps come to roughly 29 MB. Join them here and the result is roughly 29 MB as well, because when the files share a format nothing is decoded and nothing is compressed a second time. What you get back is the audio you put in, one file after another.
No account. No upload bar creeping across the screen.
How to merge audio files
- Tap the dashed box on the timeline that says Add audio files and pick your files. You can choose several at once.
- Need another one later? A + Add tile sits right after the last file on the timeline.
- Press Play and listen to the joins before you commit to anything.
- Tap Save, give the file a name, and it downloads.
Every file shows up on the timeline as its own numbered block, the same way the free online audio editor on this site shows the pieces of a clip. Below the controls runs a thin strip with one chip per file, and the ✕ on a chip drops it from the join. Undo reaches back 400 steps, which in practice means you can't really paint yourself into a corner.
What comes out depends on what goes in
Most joiners convert every file before they start. The best known of them, 123Apps' Audio Joiner, says on its own page that it automatically converts what you give it to MP3. Convenient, yes. It is also a second round of lossy compression stacked on top of the first. Once is usually fine; every extra round takes a little more, and it never comes back.
This audio merger only converts when there is no way around it:
| You add | You get |
|---|---|
| MP3s alike | One MP3. Same sample rate and channels, so the frames are copied byte for byte, and a fresh header is written so players show the true length. |
| WAVs alike | One WAV, with the samples copied untouched. |
| A mix | MP3 with WAV, or 44.1 kHz with 48 kHz: one 16‑bit WAV at the highest sample rate in the list, in stereo if any file is stereo. |
That last row is where the file size surprises people. WAV is uncompressed, about 10.6 MB for every minute at 44.1 kHz stereo and a little over 11.5 MB at 48 kHz, so an hour of mixed audio at 44.1 kHz lands around 635 MB. The MP3s inside it are decoded once and never squeezed again. They lose nothing beyond what they had already lost when someone first made them.
Used as a plain MP3 joiner, then, it is the strict one: merge MP3 files from the same album, the same recorder or the same podcast feed, and not a single frame of audio is rebuilt. When a mix does need converting, a small window over the timeline shows how far along it is. On a laptop a couple of minutes of audio is ready in about a second; a phone takes a little longer.
Cut out the bits you don't want
Joining is rarely the whole job. There's a cough at the start of part two, or twelve seconds of hiss where the recorder kept running after the talk ended. Slide the waveform until the yellow line sits on the spot and tap the scissors. The block splits there. Tap the piece you want gone, then the bin, and it's out.
A cut lands on a whole MP3 frame, which is about 26 milliseconds at 44.1 kHz, or on a single WAV sample, so nothing gets smeared around the edit. Want a fade at the end, or the second file a little louder? Save the join, then open it in the audio editor linked above. It changes volume and adds fades without re‑encoding either.
Nothing leaves your device
There is no server behind this page. It joins audio files the way a desktop program would, on the machine in front of you: your files are read straight off your phone or computer, joined in the page, and the finished file goes to your downloads. That is why a large WAV starts opening at once instead of waiting on an upload, and why a recording you would rather keep to yourself stays that way. Whether you are merging two audio files or twenty, the same holds.
Where it stops
- MP3 and WAV only. M4A, AAC, OGG, FLAC and OPUS files are turned away with a note saying so, rather than being quietly converted.
- The order is the order you add them. To move a file, remove its chip and add it again with the + tile; it goes to the end. If order matters, adding files one at a time is the surest way.
- No crossfade. Files meet end to end. I left crossfades out on purpose, because an overlap can't be built without re‑encoding it.
- A hair of silence between MP3s. Every MP3 encoder pads the start and end of a file, usually by somewhere between 25 and 50 milliseconds all told, and a join that doesn't re‑encode keeps that padding. Most ears never notice. WAV joins have no gap at all.
- WAV tops out at 4 GB. That is roughly six and three‑quarter hours at 44.1 kHz stereo. The tool tells you before it gets there.
Found a file that ought to open and won't? Write to me with what it is and where it came from. The rest of the audio tools on this site are listed on the Audio Tools page, and everything else is on the Critical Monk home page.
Questions people ask
How do I merge audio files online for free?
Open this page, tap Add audio files on the timeline and choose your MP3 or WAV files. Press Save and the joined file downloads. There is no sign‑up and nothing to pay.
Can I join MP3 files without losing quality?
Yes, as long as the MP3s share a sample rate and channel layout, which is the usual case for files from one source. Their frames are copied as they are, so the joined MP3 sounds exactly like the originals. If the rates differ, the result is made as a WAV instead.
Can I combine MP3 and WAV files into one file?
Yes. The combined file is a WAV. The MP3s are decoded once rather than re‑encoded, and everything is brought to the highest sample rate in your list.
Are my audio files uploaded anywhere?
No. They are read and joined in your browser, on your own device, and nothing is sent to a server.
How many audio files can I join?
There is no fixed limit. A very long list is bounded by your device's memory, and a WAV result cannot pass the format's 4 GB ceiling.
Can I change the order of the files?
Files join in the order you add them. To move one, remove it with the ✕ on its chip and add it again with the + tile at the end of the timeline.
Can I cut out part of a file before joining?
Yes. Put the line on the spot, tap the scissors to split the block, tap the piece you don't want and tap the bin. Undo brings it back if you change your mind.
Why is there a tiny gap between two MP3 files?
MP3 encoders pad each file with a few milliseconds of silence at both ends. Joining without re‑encoding keeps that padding, so a join can carry a pause of a few hundredths of a second. WAV files join with no gap.
Does it work on a phone?
Yes. It runs in the phone's browser, so there is no app to install. Tap to add files, drag the waveform to move through them, and save the result to your phone.