Audio Joiner Free Online
Join multiple audio files into a single track with this free online tool. Add MP3, WAV, M4A, OGG, or FLAC files, trim each one to the exact part you need, set the order, and add crossfades between them. Everything runs in your browser and your files are never uploaded to any server.
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- Only upload files you have the right to use. Copying or sharing other people's music, videos or recordings without permission can violate copyright law. FreeSoundTools does not store your files on a server.
When to use it
- Combine voice memos or interview recordings into one file
- Build a music medley or workout playlist as a single track
- Add intro and outro music to a podcast episode
- Join split recordings from your phone or voice recorder
How to use
- Drop two or more audio files into the box (or add more later).
- Set the start and end time for each file, or keep the whole thing.
- Drag rows or use the arrows to reorder the files.
- Set crossfade length (0 for a hard cut between files).
- Choose MP3, WAV, or FLAC and press Save to download.
How it works
Each file is decoded in your browser, trimmed to the range you set, joined in order with optional crossfades, and exported using built-in MP3, WAV, or FLAC encoders. Nothing is uploaded to a server. The total length is limited only by your device memory. How to verify. Also available as a free REST API for developers and AI agents (edge-processed, zero retention).
Also available as: Merge MP3 Files
FAQ
How many files can I join?
There is no fixed limit. The total length depends on your device memory. On phones, keep it under about an hour for best performance.
Can I trim each file before joining?
Yes. Each file has its own start and end time fields with 0.01-second precision.
What audio formats are supported?
Input: MP3, WAV, M4A, OGG, FLAC, AAC, MP4, WebM. Output: MP3, WAV, FLAC.
What is crossfade?
Crossfade overlaps the end of one file with the start of the next, creating a smooth transition. Set to 0 for a direct cut.
Are my files uploaded to a server?
No. All processing happens in your browser. Files never leave your device.
Last checked: October 10, 2026 · FreeSoundTools team