How do I merge audio files online for free?

Upload your audio files at audio-join.com, optionally trim each one, select output format (MP3, WAV, OGG, M4A, FLAC, AAC, OPUS, WebM), and click Merge and Download. Everything runs in your browser.

Can I merge audio files and save as M4A?

Yes. Audio-Join.com uses mp4box.js to properly wrap AAC audio into a real M4A/MP4 container, entirely in your browser. M4A files work perfectly on iPhone, iPad, Mac, and iTunes.

Are my files uploaded to a server?

No. All processing happens 100% in your browser. Files never leave your device.

🎵 Audio File Merger

Upload audio files, trim each track if needed, then merge into one seamless file — output as MP3, WAV, M4A, OGG, OPUS, FLAC, AAC or WebM, all in your browser

Click to upload audio files

MP3, WAV, M4A, AAC, OGG, FLAC, WMA — drag & drop supported

⚠ Max 50 MB per file

Your Files Drag to reorder · ✂ Trim · 🔊 Preview

ℹ️ Add at least one more audio file to enable merging

Output Format

Gap Between Files (sec)

MP3 Quality (kbps)

Processing…

✓

Merge Complete!

⬇ Download Merged File

⚡ Why Use Audio-Join.com?

Our free online audio merger combines multiple audio tracks into one file without uploading anything to a server. Everything runs in your browser — including the MP3 encoder. Your files stay 100% private.

🔒

100% Private

Files never leave your device. No upload, no storage, no tracking.

✂️

Trim Before Merging

Set start/end points per track with visual waveform handles.

🔊

Preview Each Track

Play any file before including it in the final merge.

↕️

Drag to Reorder

Change the track order with simple drag and drop.

🎛

8 Output Formats

MP3, WAV, M4A, OGG, OPUS, FLAC, AAC, WebM — pick what you need.

⚡

Instant Processing

No queue, no wait. Merging starts the moment you click.

📋 How to Merge Audio Files Online

Step 1 — Upload: Click the upload area or drag and drop your audio files onto audio-join.com. Each file must be under 50 MB. You need at least 2 files to merge.

Step 2 — Trim (optional): Click ✂ next to any file. Drag the green handles on the waveform to set start and end trim points. Click Preview to hear the trimmed section.

Step 3 — Reorder: Drag files up or down to change the playback sequence.

Step 4 — Choose format: Select from MP3, WAV, M4A, OGG, OPUS, FLAC, AAC, or WebM.

Step 5 — Merge & Download: Click the button. Your merged audio is processed and downloaded immediately — no email, no account required.

🎵 Output Format Guide

Audio-Join.com supports more output formats than any other browser-based audio merger, using native browser APIs and JavaScript encoder libraries:

Format	Quality	Best For
MP3	Up to 320 kbps	Music, podcasts, sharing — widest compatibility
WAV	Lossless 16-bit PCM	Professional audio, editing, archiving
M4A	Lossless PCM (Chrome) or AAC (Safari)	iPhone, iPad, Mac, iTunes, Apple Music
OGG	Vorbis/Opus codec	Open format, good compression, web use
OPUS	Best at low bitrates	Voice recordings, calls, streaming, small files
FLAC	Lossless compressed	High quality archiving, audiophiles
AAC	Varies by browser	Mobile devices, streaming platforms
WebM	Opus codec	Web streaming, YouTube, modern browsers

❓ Frequently Asked Questions

Can I export merged audio as MP3 at Audio-Join.com?

Yes! Audio-Join.com uses the open-source lamejs JavaScript library to encode MP3 entirely in your browser. Select "MP3" as the output format and choose your quality (up to 320 kbps). No server is involved.

Can I merge audio and save as M4A for iPhone or iTunes?

Yes! Audio-Join.com uses mp4box.js to create a proper M4A file (AAC audio in an MP4 container) entirely in your browser. M4A files play natively on all Apple devices — iPhone, iPad, Mac — and import perfectly into iTunes and Apple Music.

What is OPUS format and when should I use it?

OPUS is a modern audio codec that delivers the best audio quality at low file sizes. It's ideal for voice recordings, podcasts, phone calls, and any audio where you want small file size without sacrificing quality. It outperforms MP3 at the same bitrate.

How many files do I need to merge?

You need at least 2 audio files to use the merge feature. If only one file is uploaded, the Merge button will not appear — add a second file to enable it.

Does merging reduce audio quality?

WAV and FLAC output are fully lossless. MP3, OGG, OPUS, M4A, and AAC use compression — quality depends on the bitrate. For best quality, use WAV or FLAC. For Apple devices, use M4A.

What is the file size limit?

Each individual audio file can be up to 50 MB. There is no limit on the number of files you can merge. Very large files take longer to merge.

Are my audio files uploaded to a server?

No. All audio decoding, trimming, merging, and encoding happens 100% in your browser. Your files are never uploaded, stored, or sent anywhere.

Can I trim each audio track before merging?

Yes! Click the ✂ icon next to any file to open the trim panel. A visual waveform appears — drag the green handles to set the start and end trim points. Preview the trimmed section with the Play button before merging.