Join audio files into one continuous file: matching files merge with zero re-encoding, differing files decode once, and the result line always names the path taken.
Your files are processed in your browser, on your own device. Nothing is uploaded to a server.
Merging audio makes several files into one continuous file: podcast segments, audiobook chapters, song parts, a row of voice notes in order. This tool runs in your browser and follows a strict rule that the result line enforces: it never silently converts your files. What happened to your sound is printed on the result, every time.
The rule works like this. When every file matches (same format, sample rate and channels), the join is a stream copy: the sound is not re-encoded at all and nothing is lost. When files differ, they are decoded once to a common shape and encoded once to your chosen output. Some well-known joiners quietly convert everything to MP3 whatever you gave them. This page treats that as the behaviour to beat, not to copy.
1. Drop the files into the box, up to 30, and drag them into the order you want. Order is the product on this page.
2. Choose the join style: butt join, a silence gap, or a crossfade. Add loudness matching if the parts were recorded at different levels.
3. Press Merge the Files and read the result line: it names the path taken and, on a rebuild, what differed.
A butt join is free: files touch, nothing between, and on matching files it costs no encode. A silence gap (half a second to five) and a crossfade (the same range) are built from decoded sound, so choosing either one moves the job to the rebuild path, and the settings panel says so before the run rather than letting you discover it after. Crossfades suit music parts. Gaps suit chapters and segments. Loudness matching, also a rebuild extra, brings every file to a shared loudness before joining, which is the difference between a smooth listen and reaching for the volume knob between chapters.
The engine note: the work runs on the encoder inside your browser, about 31 MB downloaded once and cached, and your audio never leaves the device. Rebuild outputs offer MP3, WAV, M4A, OGG and FLAC. The copy path keeps the source format.
Two named limits: mixed sample rates on the copy path are a refuse-and-explain case, never a silent resample (the rebuild handles them properly), and joining audiobook MP3s by copy keeps no chapter marks, because the joined file is one continuous track. To cut one file into parts instead, split audio is the page. To fix levels on a single file, normalize audio goes deeper. More in the audio tools collection.
The two jobs that fill this page’s queue share a shape: several same-format recordings, recorded on the same setup, that belong together. Same voice, same mic, same export settings means the copy path applies, the merge is fast, and the result is the original sound in a longer file. When a guest segment arrives from a different setup, the rebuild path with loudness matching is the one that saves the episode.
Add MP3 files that share the same sample rate and channels, leave the style on butt join, and the tool joins them by stream copy. The result line confirms no re-encode happened.
Yes. Mixed formats, rates or channels take the rebuild path: one decode to a common shape and one encode to your chosen output. The result names what differed.
Choose the crossfade style and its length. Because an overlap is built from decoded sound, the job re-encodes once, and the panel states that cost before you run.
On the copy path, no: the sound is untouched. On the rebuild path, there is exactly one encode, at a sensible bitrate, and the result line tells you it happened.
No. The joined file is one continuous track. The page says so up front because audiobook listeners are the people most likely to care.
Up to 30 in one run, each up to the 500 MB ceiling, with drag-to-reorder before you run.
Same rules as this one: free, in your browser, with nothing uploaded.
MP3, WAV, M4A and OGG, swapped in seconds.
Cut a ringtone or a clip out of any song.
Heavy WAV files made small enough to share.
Voice memos and iTunes files as plain MP3s.
An MP3 opened back up into a full WAV file.
OGG files, often from games and apps, as MP3s.
Big FLAC songs made small enough for a phone.
An MP3 saved as OGG for games, apps and the web.