How to use
- Select or drop the audio file you want to fade.
- Enter the fade-in and fade-out lengths in seconds (set either to 0 to skip it).
- Click Apply and wait for the fade to finish processing.
- Download your faded audio as an MP3.
Frequently asked questions
What do the fade-in and fade-out do?
They create a smooth volume ramp at the edges of your track: the audio rises from silence over the fade-in seconds and eases back to silence over the fade-out seconds, so there are no abrupt starts or hard cut-offs.
What audio formats can I use?
You can load common audio files such as MP3, WAV, M4A, AAC, and OGG. Whatever you drop in, the faded result is always exported as an MP3.
Can I add only a fade-in or only a fade-out?
Yes. Set either field to 0 to skip that side — for example a 2-second fade-in with a 0-second fade-out only ramps up at the start, and vice versa.
Is my audio uploaded anywhere?
No. Everything runs locally in your browser and your files never leave your device. The first run downloads a one-time ~30 MB engine that is then cached, so later fades even work offline.
Will fading change the audio quality?
The fade itself only adjusts volume smoothly and does not degrade the sound. The output is re-encoded to a high-quality MP3, which is a lossy format, so it is close to the original but not a bit-perfect copy.
The fade-out was skipped on my file — why?
The fade-out needs the track's length, which the browser reads from the file. A few formats can't always be decoded by the browser (for example FLAC or Opus in Safari, WMA, AMR, or AIFF); in that case only the fade-in is applied. Converting to MP3 or WAV first usually fixes it.
About this tool
Add a fade-in and fade-out to any audio file free in your browser. Set the ramp in seconds and export an MP3 — no uploads, everything runs locally.