Trim, Compress & Convert Audio
Trim audio clips, compress file size, adjust bitrate, and convert between formats — all inside your browser. Powered by FFmpeg.wasm. Nothing is uploaded to any server.
Ready.
How to Use
Alfreto's Audio Toolkit is a free, all-in-one audio processing tool that runs 100% inside your browser. To get started, click Choose Audio or drag and drop your audio file into the upload area. Supported input formats include MP3, WAV, AAC, OGG, FLAC, OPUS, and M4A. Once loaded, the source audio is previewed and its duration and file size are displayed automatically.
Choose one of the three Operations: Trim to cut a clip between a start and end time using the interactive timeline — drag the handles or type exact times; Compress to reduce file size by targeting a lower bitrate and optionally converting stereo to mono; and Convert to change the audio format (e.g. MP3 → WAV, OGG → AAC) with your choice of output bitrate. You can combine operations by adjusting settings across multiple tabs — the tool will apply them all in one FFmpeg pass.
Click Process when you are ready. A progress bar shows FFmpeg's real-time progress. When finished, the output audio is shown in the preview panel alongside file size stats. Click Download to save the result. All processing uses FFmpeg.wasm — everything stays on your device.
FAQ
Is my audio file uploaded to a server?
No. All processing happens locally in your browser using FFmpeg.wasm. Your audio file never leaves your device at any point.
Which browsers are supported?
All modern browsers are supported — Chrome, Edge, Firefox, and Safari. FFmpeg runs in single-thread mode which works universally without requiring any special server headers.
How do I trim an audio file?
Select the Trim tab. Drag the pink handles on the timeline to set start and end points, or type the exact times in the fields below (format: hh:mm:ss or mm:ss). Then click Process. The output keeps the same format as the input.
What bitrate should I use for compression?
For music, 128–192 kbps is a good balanced range. For voice recordings and podcasts, 64–96 kbps is sufficient and keeps file sizes small. 320 kbps gives the highest quality closest to the original.
What is the difference between WAV and FLAC?
Both are lossless formats — they preserve the full original quality. WAV is uncompressed and produces larger files, while FLAC uses lossless compression for smaller file sizes with identical audio quality. For archiving or editing, either is an excellent choice.
Can I convert MP3 to WAV or WAV to MP3?
Yes. Use the Convert tab to select any output format. You can convert from any supported input (MP3, WAV, AAC, OGG, FLAC, OPUS, M4A) to any output format. For MP3 and AAC outputs, select your desired bitrate from the dropdown.
Why does it take time on first load?
FFmpeg.wasm (~10 MB) is downloaded from a CDN on first use. Subsequent uses within the same browser session are instant because the engine is cached.
Is there a file size limit?
There is no hard limit, but very large files (over 500 MB) may run into browser memory limits. For best results, process files under 200 MB.