Merge Audio Online
Processing entirely on your device — large files may take a moment.
Drop the files in the order you want them joined and the concat demuxer stitches them with stream copy — packets are concatenated as-is, so an hour of audio merges in seconds with zero quality loss. The queue order IS the output order.
Clips must share the same format and parameters (sample rate, channels) for a clean stream-copy join — recordings from the same source always do. Mixed formats should be converted to one format first.
How to merge audio
- 1
Select your files
Drag & drop your MP3 files onto the area above, or click to browse. You can add multiple files at once for batch conversion.
- 2
Convert instantly
Click "Convert to MP3". The conversion runs entirely inside your browser using WebAssembly — no upload, no queue, no waiting.
- 3
Download results
Download each converted MP3 file individually, or grab everything at once as a ZIP archive.
About the MP3 format
MP3 (MPEG-1 Audio Layer III) defined digital music: standardized in 1993, popularized by Napster and the first portable players, and freed of all patents in 2017. It is lossy psychoacoustic compression — it discards frequencies the ear supposedly won't miss — at bitrates from 128 to 320 kbps, with ID3 tags carrying title, artist and cover art.
Twenty years of competitors have failed to displace it, because playback support is absolute: every device that has ever played music plays MP3. At 320 kbps even critical listeners struggle to identify it in blind tests, though modern codecs reach the same quality at noticeably lower bitrates.
+Strengths
- ✓Plays on absolutely everything
- ✓Rich tag ecosystem (ID3, cover art)
- ✓320 kbps is transparent for most listeners
!Limitations
- −Lossy ceiling — never a mastering format
- −Less efficient than AAC/Opus at equal quality
- −Low-bitrate artifacts are audible and permanent
Frequently asked questions
Can I mix MP3 and WAV in one merge?
Not with stream copy — convert everything to one format first (MP3 for size, WAV for lossless), then merge.
Is there a gap between tracks?
No — concat places packets back-to-back. Note MP3 adds tiny encoder-padding frames at file ends; gapless merging of MP3 is inherently approximate, WAV/FLAC are exact.
How many files can I merge?
No hard limit — everything must fit in browser memory together; a few hundred MB total is the practical ceiling.