Merge MP3 Online — Join Audio Files
Combine multiple MP3, WAV or M4A into one file — in your browser, no quality loss. Drag to reorder, optional crossfade. Free, no sign-up.
Drop audio files here or pick several at once
MP3, WAV, M4A, OGG, FLAC, AAC — multiple files
About this audio merger
This is an online MP3 merger that runs entirely in your browser. Drop several audio files in, drag them into the order you want with up/down arrows, optionally add a smooth crossfade — and download the result as MP3 (via lamejs) or lossless WAV.
All common formats are supported: MP3, WAV, M4A (iPhone AAC), OGG, FLAC, OPUS — anything the Web Audio API can decode. Files with different sample rates are normalized to a common rate (the first track's), and channels are mixed up to the highest channel count among inputs.
Nothing is uploaded — your files and the merged result stay on your device. No sign-up, no watermarks, no rate limits, no ads inside the audio. Works on desktop and mobile.
Where it helps
A mix of favourite tracks
Stitch 5–10 favourite tracks into one MP3 — for a workout, road trip or party. A 1–2 second crossfade removes the abrupt gap between songs.
Lecture or interview in parts
Glue separate chunks of a lecture, interview or talk into a single continuous file — easier to share with listeners and students, no switching between files.
Podcast takes
If a podcast was recorded in multiple takes, merge them into one track before editing. WAV export keeps full quality for further post-production.
Mashup of song parts
Combine the intro of one song with the verse of another and the chorus of a third. With a smooth crossfade, you'll get a clean mini-mashup without abrupt cuts.
FAQ
Can I merge files of different formats?
Yes. Drop in MP3, WAV, M4A — all of them are decoded by the Web Audio API into raw PCM, merged together and re-encoded into your chosen output format (MP3 or WAV). Different sample rates are normalized automatically.
Is quality preserved when merging?
Export to WAV is lossless, no quality is lost. Export to MP3 means one re-encode step (inputs → PCM → MP3); at 192–320 kbps the difference is inaudible by ear. For important masters, prefer WAV.
Can I reorder the files?
Yes. Each file in the list has ▲ and ▼ arrows — click to move it up or down. You can also remove any track with the ✕ button or drop in additional files at any time — they'll be appended to the end.
What is a crossfade?
A crossfade is an overlap where the end of one track fades out while the start of the next fades in. The result is a smooth transition without clicks or jarring cuts. The slider lets you set the crossfade length from 0 to 3 seconds.
How many files can I merge?
There's no hard limit — dozens of tracks merge fine. The bottleneck is browser memory: decoded PCM lives in RAM, so an extremely long mix on a low-end device can fail. A typical 1–2 hour compilation works on any modern laptop or phone.
Are files uploaded to a server?
No, everything runs locally. Files are decoded by the Web Audio API in your browser, the merge runs over audio data in memory, MP3 is encoded by lamejs (also in the browser), WAV is assembled from PCM samples. You can disconnect from the internet after the page loads — merging still works.
Does it work on mobile?
Yes — Safari on iPhone and Chrome on Android both support multi-file upload, reordering, and download. On iPhone the first preview tap may be required (iOS policy), but the merge itself and export work right away.