UtilityKit

500+ fast, free tools. Most run in your browser only; Image & PDF tools upload files to the backend when you run them.

Audio Merger

Concatenate multiple MP3, WAV, M4A, OGG or FLAC files into one continuous audio track. Drag to reorder, set output format and bitrate, then download.

About Audio Merger

Audio Merger concatenates two or more audio files into one continuous track. Drop in MP3, WAV, M4A, OGG or FLAC files, drag the rows up or down to set their playback order, pick an output format and bitrate, and download the merged result. The tool uses ffmpeg's concat filter so files of different bitrates, sample rates and codecs merge cleanly into a single output — no audible click or gap between tracks. Everything runs locally via ffmpeg.wasm; files never leave your device. There is no signup, no watermark, no daily cap. Use it to stitch a podcast intro, episode and outro into a master file, glue chapter recordings of an audiobook into one playable file, or build a continuous DJ set from individual tracks.

Why use Audio Merger

  • Mix files with different sample rates, channel counts and codecs cleanly
  • Drag-style reordering (↑ / ↓ controls) before merging
  • Local ffmpeg.wasm — files never leave the browser
  • Free with no watermark, signup or daily quota
  • Output to MP3, WAV, OGG or M4A — pick what plays on your target device
  • Cached engine: subsequent merges start instantly

How to use Audio Merger

  1. Drop two or more audio files onto the upload area, or click to pick them.
  2. Use the ↑ / ↓ buttons to reorder the queue — the topmost file plays first.
  3. Click × on any row to remove a file from the queue.
  4. Pick an output format and bitrate (bitrate ignored for lossless WAV).
  5. Click 'Merge & Download' and wait for ffmpeg.wasm to finish.
  6. Preview the merged result in the inline player, then download.

When to use Audio Merger

  • Glueing a podcast intro, episode and outro into a master MP3
  • Combining audiobook chapters into a single playable file
  • Concatenating short voice memos into a daily journal track
  • Joining DJ set segments recorded separately
  • Stitching an audio drama recorded scene-by-scene
  • Bundling a meditation track with its background music

Examples

Podcast master

Input: intro.mp3 (30s) + episode.mp3 (40min) + outro.mp3 (15s)

Output: Continuous MP3 ready for upload to your host

Audiobook compilation

Input: Chapters 1–10 as separate M4A files

Output: One M4A track playable as a single 'audiobook' on iOS/Android

DJ set

Input: Six recorded WAV segments at 48 kHz

Output: One continuous MP3 at 320 kbps for SoundCloud upload

Tips

  • All files are normalised through the same encoder, so mixing 44.1 kHz and 48 kHz inputs is fine — the output uses one consistent format.
  • If tracks should fade into each other rather than hard-cut, fade the source files first; this tool does pure concatenation.
  • For a clean podcast master, normalise loudness first (use the Loudness Normalizer) so chapters aren't all different volumes.
  • If one file is mono and another stereo, the merged output will use the higher channel count and duplicate mono into both channels.
  • Re-encoding compounds lossy artifacts. If quality matters, work from the highest-quality sources you have.

Frequently Asked Questions

Are tracks crossfaded?▾
No. The merger does pure concatenation — sounds end where the previous file ends and start where the next file starts. Add crossfades in a DAW first if you need them.
Can I use files of different formats?▾
Yes — drop in any mix of MP3, WAV, OGG, M4A and FLAC. ffmpeg unifies them through a single output codec.
Does the order matter?▾
Yes — files play top to bottom in the queue. Use the ↑ / ↓ buttons to set the order before merging.
Is there a maximum number of files?▾
No hard cap. Practical limit is browser memory — typically dozens to hundreds of short files, fewer for hour-long ones.
Why does the merged file have a different bitrate than my sources?▾
All inputs are re-encoded to the bitrate you chose in the slider, ensuring a single consistent output.
Will quality drop?▾
Yes a little for lossy outputs (MP3 / OGG / M4A), since merging requires re-encoding. Pick WAV if you need a lossless intermediate.
Are my files uploaded anywhere?▾
No. ffmpeg.wasm runs in your browser; the files never leave your device.
What if one file is corrupt?▾
ffmpeg will fail with an error message. Remove the offending file and try again.

Explore the category

Audio Compressor Shrink MP3, WAV, M4A, OGG and FLAC files by re-encoding at a lower bitrate. Choose 32–320 kbps, pick MP3, OGG or M4A output, then download. 100% browser-side via ffmpeg.wasm. Audio Format Converter Convert audio between MP3, WAV, OGG, M4A and FLAC in your browser. Choose bitrate or sample rate, then download. Runs locally via ffmpeg.wasm — no uploads. Audio Reverser Reverse any audio file so it plays backwards. Drop MP3, WAV, M4A, OGG or FLAC, choose output format, and download. ffmpeg.wasm areverse — no upload. MP3 Cutter & Audio Trimmer Trim MP3, WAV, M4A and OGG audio with a visual waveform editor. Set start and end with sliders, preview the selection, then download. Audio Loudness Normalizer (LUFS) Normalize loudness of MP3, WAV, M4A, OGG and FLAC files using ffmpeg loudnorm (EBU R128). Hit Spotify, podcast or broadcast targets — runs locally via ffmpeg.wasm. Audio Speed & Pitch Changer Speed audio up or slow it down without changing pitch, or shift pitch in semitones independently of speed. MP3, WAV, M4A, OGG, FLAC. ffmpeg.wasm in browser.

Glossary

Concatenate
Stick two or more audio files together end-to-end into one continuous track.
Concat filter
ffmpeg's filter graph for joining multiple audio streams. Re-samples and remuxes as needed for clean joins.
Bitrate
Kilobits per second of compressed audio. Used here for lossy outputs only.
Sample rate
Audio samples per second (e.g. 44.1 kHz, 48 kHz). Concat filter normalises all inputs to one rate.
Channel layout
Mono (1 channel) or stereo (2 channels). Concat unifies layouts across the queue.
Lossless
WAV output preserves every sample without further compression; useful when you'll re-edit the merged file.