Fade an audio file in and out smoothly and change its volume in dB - as a PCM envelope right on the samples, locally in the browser, no upload.
Running locally on your device ...
Running locally on your device ...
0%
Your files never left your device
No. Everything runs in your browser - your file never leaves your device. How this is verifiable
A hard start, an abrupt end or a recording that is simply too quiet: this tool applies a volume envelope right on the audio samples - a linear fade-in at the start, a linear fade-out at the end and a constant boost or cut in decibels in between.
For orientation on dB values: -6 dB halves the amplitude, +6 dB doubles it; plus/minus 3 dB is a clearly audible but moderate change. With positive gain, peaks are hard-limited at full scale so no invalid, clipped-beyond-range samples are ever written - if you need a big boost, consider loudness normalization instead.
Everything runs locally: the file is decoded in the browser, processed sample by sample and re-encoded (lossless WAV or M4A). Nothing is uploaded.
| Input formats | MP3, WAV, M4A, AAC, OGG, OPUS, FLAC |
|---|---|
| Auto-conversion | MP4 |
| Output formats | WAV, M4A |
| Batch processing | No |
| Processing | Locally in your browser (WebCodecs) |
| File upload | None |
Limitations: Honest per-device length cap (desktop about 20 minutes, tablet 15, phone 10; more with plenty of memory) - longer files are clearly refused, never silently truncated. A fade-out needs a known total length; containers without one are refused honestly instead of guessed. Linear ramps (no S-curve fade). For level-accurate matching to streaming standards, loudness normalization (LUFS) is the better tool.
No, all processing runs locally in the browser.
Decibels are logarithmic: -6 dB halves the amplitude, +6 dB doubles it. 0 dB leaves the volume unchanged.
Peaks are hard-limited at full scale - invalid samples are never written, but a very strong boost can limit audibly. Use normalization instead in that case.
This tool changes volume by a fixed factor. Normalization measures perceived loudness and matches a target (LUFS) - better for podcast/streaming specs.
Yes - set the other time to 0. A pure volume change without fades also works (both times 0).
Trim audio · Ringtone maker · Merge audio files · Normalize audio