Merge Audio

Combine several audio files into one track. Add your files, drag them into order, choose a gap or a smooth crossfade between them, optionally even out their volumes, and download the merged result as a WAV file. Files are decoded and joined on your device — nothing is uploaded.

How to merge audio files

1. Add two or more audio files — MP3, WAV, M4A, OGG or any format your browser can play. You can add more files at any time.
2. Put them in order with the ↑ and ↓ buttons; remove any with ×.
3. Choose how to join them: back to back, with a gap of silence, or with a crossfade.
4. Set the gap or crossfade length in seconds.
5. Choose whether to normalise loudness so quiet and loud files sound similar.
6. Click “Merge & download WAV”. The merged track also appears in the player so you can listen.

All files are converted to the same sample rate when they are decoded, so recordings made at different settings can be joined without problems.

Gap, back to back or crossfade?

A crossfade overlaps the end of one file with the start of the next, fading one out while the other fades in. One to three seconds is typical for music; longer crossfades suit ambient sound.

What normalising does

Recordings often come in at very different volumes — a phone memo might be much quieter than a downloaded track. Normalising scales each file so its loudest peak reaches the same level (just below full scale), which makes the merged track more even. It is peak normalisation, not a loudness-matching algorithm, so two files with the same peak can still sound somewhat different in loudness; it is a quick, safe way to avoid big jumps in volume.

Common uses

• Podcasts and interviews — join intro music, the recording and an outro.
• Audiobooks and lectures — combine chapters or parts into one file.
• Music practice — build a single practice track from several songs or exercises.
• Voice messages — combine several voice memos into one file to share.
• Events — make one continuous track for a presentation, ceremony or class.
• Language learning — join short dialogues into a longer listening exercise.

Worked example

A teacher has five voice-memo recordings of a story, each between two and four minutes, recorded at different volumes on a phone. They add all five, check the order, choose a 1.5-second gap and turn on normalisation. The merger produces a single 16-minute WAV with even volume and short pauses between parts, which they play in class and convert to MP3 for the school’s learning platform.

About the output file

The merged file is an uncompressed 16-bit WAV at your device’s audio sample rate (usually 44.1 or 48 kHz), stereo if any input is stereo. WAV files are large — about 10 MB per minute in stereo — but play everywhere and lose no further quality. Convert to MP3 or AAC in any audio app if you need a smaller file for sharing. Very long merges may be too large for the browser’s memory, especially on phones.

Tips for clean joins

• Trim silence or noise from the start and end of each file before merging.
• If back-to-back joins click, use a very short crossfade (0.05–0.1 s).
• Keep a copy of the original files in case you want to change the order later.
• For spoken audio, a gap of 1–2 seconds sounds natural between segments.
• Check the merged file from start to finish before sharing.

Preparing files before merging

1. Listen to each file and note any noise, long silences or false starts.
2. Trim unwanted parts in a simple audio editor or with the trim tool of your choice.
3. Name files with numbers (01-intro, 02-interview) so the order is obvious.
4. Add them to the merger in order, then check the list.
5. Merge, then listen to the joins — the moments where one file becomes the next.

Most problems in merged audio — clicks, sudden volume changes, awkward pauses — are easiest to fix in the individual files before merging.

Sample rates and channels

Audio files can differ in sample rate (for example 44.1 kHz from music and 48 kHz from video) and in channels (mono voice memos, stereo music). When your browser decodes each file, it converts it to the same sample rate automatically, and the merger outputs stereo if any input is stereo, copying mono files to both channels. That means you can mix sources freely without converting them first.

Copyright

Merge recordings you made or have permission to use. Combining commercial music into a single file for sharing or publishing may infringe copyright.

Privacy

Everything happens in your browser with the Web Audio API. Your files are not uploaded, stored or shared.