Audio Joiner
Merge and join multiple MP3, WAV, M4A, OGG, and FLAC audio files into one track online for free. No upload, works in your browser.
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Frequently asked questions
- How do I merge MP3 files online for free?
- Click Add Audio Files to select two or more MP3, WAV, M4A, OGG, or FLAC files, drag items in the list to set the order, pick an output format (MP3, WAV, or M4A), then click Join Audio. Your merged track can be previewed and downloaded without any upload.
- Is my audio uploaded to a server?
- No. All processing happens directly in your browser using FFmpeg compiled to WebAssembly. Your audio files never leave your device, which keeps your content private and works even on slow connections.
- Which audio formats can I join?
- The tool accepts MP3, WAV, M4A, AAC, OGG, FLAC, Opus, and WebM audio. You can mix different input formats in one merge — the tool will automatically normalize tracks to a common format before concatenation so the final file plays back smoothly.
- Is there a file size or number-of-files limit?
- There is no hard limit set by the tool itself, but because merging runs entirely in your browser, very large jobs (many hours of audio or dozens of big files) depend on your device memory. For most everyday cases — joining songs, podcast segments, or voice notes — it works without issue.
- Can I reorder tracks before joining?
- Yes. Each file appears in a list where you can drag-and-drop to reorder, use the up and down arrow buttons, or remove items with the X button. The final merged audio follows the exact order shown in the list.
- What output format should I choose?
- Pick MP3 (192 kbps) for the best balance of small file size and broad compatibility — it works everywhere. Choose WAV for lossless uncompressed quality when you plan to edit further, or M4A (AAC) for efficient compression that works well on Apple devices.