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Merge audio files online - join MP3, WAV and more into one track

Add your recordings, put them in order and combine them into a single file, with an optional pause or a smooth crossfade between tracks. Everything happens locally in your browser.

  • Free
  • No sign-up
  • Private
  • Runs locally

Drag & drop files here

or click to choose from your device

MP3, WAV, M4A, OGG, FLAC · any number of files

How to merge audio files

  1. 1.

    Add files

    Drop at least two audio files onto the area above. You can add more at any time and mix formats.

  2. 2.

    Set the order

    Drag items in the list or use the arrows. The first item plays first.

  3. 3.

    Choose the transition

    Pick Gap (silence) or Crossfade and set the time with the slider, from 0 to 5 s in 0.5 s steps.

  4. 4.

    Merge and download

    Choose MP3 or WAV, click "Merge files" and download merged.mp3 or merged.wav.

Gap or crossfade?

  • Gap (silence) inserts silence of the chosen length between tracks. Use it for lectures, audiobook chapters and voice messages. At 0 s the files are simply butted together.
  • Crossfade fades the ending track out while the next one fades in, overlapping them. It suits music and DJ-style mixes; the total length shrinks by the overlap.

Example: two 3:00 tracks with a 2 s crossfade give 5:58; with a 2 s gap they give 6:02. A crossfade can never be longer than half of the shorter of the two neighbouring tracks.

Calculating the final length and size

With a gap the length is the sum of all tracks + (number of tracks - 1) × gap. With a crossfade it is the sum - (number of tracks - 1) × overlap. Five 12-minute audiobook chapters with a 1.5 s gap: 60 min + 4 × 1.5 s = 60:06.

MP3 size is roughly bitrate × seconds ÷ 8, so an hour at 192 kb/s is about 86 MB. WAV (16-bit stereo, 44.1 kHz) needs around 635 MB per hour, so MP3 is the sensible choice for long sets. Total length and estimated size are shown live above the "Merge files" button.

Mixing formats, sample rates and channels

You can combine MP3 with WAV, M4A, OGG and FLAC in one go. Each file is decoded and resampled to a common 44.1 kHz. If any track is stereo the result is stereo, and mono tracks are copied to both channels. The encoder writes MP3 at 64-320 kb/s (192 kb/s by default) or 16-bit WAV, which adds no extra loss.

Files the browser cannot read are marked "cannot be read" in the list; remove them with one click or convert them first in the audio converter. Merging only works once every file in the list is readable.

Tips for a clean result

  • Name files 01, 02, 03 before adding many at once - it makes sorting the list much quicker.
  • Match loudness beforehand - the tool does not normalise levels, so a quiet recording next to a loud one stays quiet.
  • Trim silent ends with the audio cutter before using a crossfade, otherwise the overlap happens in silence.
  • Joining videos instead? Use merge videos.

Your files are never uploaded: decoding, mixing and encoding run on your device, which keeps private recordings private.

Frequently asked questions

Is merging audio files free?

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Yes, with no sign-up and no limit on the number of files.

Are my files uploaded to a server?

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No. All files are decoded and merged locally in your browser.

Can I merge files in different formats?

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Yes, for example MP3 with WAV and M4A, as long as your browser can decode each of them.

How do I change the order?

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Drag an item in the list or use the arrow buttons next to the file name.

Does merging reduce quality?

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WAV output adds no loss. MP3 output re-encodes everything, so choose 192-320 kb/s to keep it transparent.

How many files can I merge?

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There is no fixed limit, but decoded audio lives in memory - an hour of stereo sound needs well over 1 GB of RAM. Use a computer for long sets.

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