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Audio Merger

Join multiple audio files into one MP3, WAV, or M4A — decoded and normalized so mixed sources always work. 100% in-browser.

LOCAL · FFMPEG.WASMAny orderMixed formats3 outputs100% local

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Drop audio files here, or click to browse

MP3, WAV, M4A, OGG, FLAC (max 100 MB each)

Drop two or more audio files, arrange the order, and join them into one track

Data Source & Legal Disclaimer

Effective: 2026Last updated: TodayUpdate: Manual review

Sources: ffmpeg.wasm — Browser-based media processing

Audio merging runs entirely in your browser using ffmpeg.wasm. Your files are never uploaded to any server.

See all data sources & update policy →

Why this merger always re-encodes — illustrated

Audio files in the wild mix MP3 at 44.1 kHz, M4A at 48 kHz, different channel counts, and different bitrates. A packet-level stream copy only works when every parameter matches, and fails confusingly when it does not. So this tool always takes the stable path: the concat demuxer splices the playlist, then every clip is decoded and re-encoded into one consistent output — MP3 128/192/320 kbps for sharing, WAV for further editing, M4A for Apple ecosystems. One lossy generation is added for MP3/M4A (none for WAV), which is the honest price of guaranteeing that any combination of inputs just works.

Playlist → concat demuxer → decode → one consistent encode

Mixed sample rates, channel counts, and codecs are all normalized in a single pass.

Assembling a meditation track — Rhea's three parts

Rhea has a 3:20 intro (200.0 s), a 12:00 body (720.0 s), and a 2:40 outro (160.0 s) recorded as separate MP3s for her meditation app.

Queue in order:She drops intro, body, and outro; the header sums 200 + 720 + 160 = 1,080 s = 18:00.0 total
Pick the output:Her app streams M4A at 128 kbps, so she selects M4A — the mixed 44.1/48 kHz sources get normalized in the re-encode
Size math:1,080 s × 128,000 bits/s ÷ 8 = 17,280,000 bytes ≈ 16.5 MB — one consistent file for the whole session
Verify:She plays the seam at 3:20.0 (intro → body): clean handoff, no click, and the download is intro_merged.m4a

↩ Back to merger

About this tool

What is this tool?

Join multiple audio files into one MP3, WAV, or M4A. Mixed formats OK. In-browser.

Any orderMixed formats3 outputs100% local

What Is the Audio Merger?

The Audio Merger joins any number of audio files end-to-end. Clips are queued in order with live duration probing, then the concat demuxer splices them while every clip is decoded and re-encoded into one consistent MP3, WAV, or M4A output. All processing is local via ffmpeg.wasm.

How to Merge Audio Files

Drop two or more audio files, arrange them with the arrow buttons, pick an output format and bitrate, and click Merge. The total duration updates as you queue clips, and the result plays inline before download.

Frequently Asked Questions

Why does this merger always re-encode instead of copying?

Real-world audio mixes sample rates (44.1/48 kHz), channel counts, and codecs. Packet-level copying only works when every parameter matches and fails confusingly otherwise. Decoding and re-encoding into one consistent output guarantees any combination of inputs produces a clean file.

Which output format should I pick?

MP3 at 128–192 kbps for podcasts and sharing, 320 kbps for music; WAV for further editing (lossless); M4A for Apple ecosystems. WAV is 16-bit PCM and ignores the bitrate selector because it keeps every sample.

Can I control the order of clips?

Yes — clips appear in an ordered list with up/down buttons, and the header shows the summed duration of all queued clips so you know the total length before merging.