NoCloud Media

Audio tool

Audio Joiner — Combine Audio Files

Combine MP3, WAV, OGG, M4A, or FLAC files into a single track. Runs in your browser.

How it works

  1. 1

    Drop two or more audio files

    Mix and match formats — MP3, WAV, OGG, M4A, AAC, or FLAC.

  2. 2

    Put them in order

    The files join in the order they're listed. Reorder with the up/down buttons.

  3. 3

    Pick an output format

    MP3 for sharing, WAV/FLAC for lossless, OGG/M4A for smaller lossy files.

  4. 4

    Join and download

    The concat filter mixes the tracks end-to-end, re-encoding to your chosen format.

Why use Audio joiner?

Handles format mismatches — inputs can be different codecs, sample rates, or bit depths. FFmpeg's concat filter normalizes them.

Private — your audio never leaves your browser.

Predictable — the tracks join in the order you pick. No surprise cross-fades, no alignment guesses.

Common use cases

  • Stitch podcast intro + main body + outro into one MP3
  • Combine several voice memos into one audiobook-style track
  • Merge individual recorded sections of a song demo
  • Glue a sound effect onto the end of a notification tone
  • Concatenate lecture segments into a single file
  • Join a chapter-split audiobook back together

About MP3 and MP3

Joining audio files requires a common sample rate, bit depth, and channel layout. NoCloud Media pre-resamples every input to 44.1 kHz stereo before running FFmpeg's `concat` filter, so even wildly mismatched inputs (a mono 8 kHz voicemail + a 192 kHz stereo FLAC, say) combine without tripping the filter. The combined stream is then re-encoded to your chosen output format. Because this is always a re-encode, lossy → lossy loses a small amount of quality; for a bit-perfect join of identical-format files, a specialized remuxer would be faster.

Frequently asked questions

Is my file uploaded to a server?
No. NoCloud Media joins your audio entirely in your browser using WebAssembly. Nothing uploads.
Can I mix formats?
Yes — you can feed in MP3, WAV, OGG, M4A, AAC, and FLAC together. FFmpeg's concat filter normalizes them to a common format before joining.
Will I get gaps or pops between tracks?
The concat filter joins without gaps. If your inputs have leading or trailing silence you want removed, trim them first with the audio trimmer.
Can I add crossfades?
Not in this tool. Crossfades need a dedicated audio editor. NoCloud Media joins tracks end-to-end with no overlap.
How many files can I join at once?
As many as fit in your browser's memory. Files are read one at a time, but the output process holds all decoded audio in memory, so practical limits depend on total duration and sample rate.
Which browsers are supported?
Chrome, Edge, Firefox, and Safari 15+. We require WebAssembly and SharedArrayBuffer, both standard in modern browsers.

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