A fade in raises the volume from silence to full level; a fade out lowers it back to silence. Fades hide abrupt edits, make excerpts sound finished, let music sit under a voice and stop clicks at cut points. Two settings decide how a fade sounds: its length and its curve.
How long should a fade be?
There's no single right answer, but these ranges work for most material:
| Situation | Fade in | Fade out |
|---|---|---|
| Removing a click at a cut | 10–30 ms | 10–50 ms |
| Notification or text tone | 10–30 ms | 0.2–0.5 s |
| Ringtone (loops while ringing) | 0–0.5 s | 1–2 s |
| Excerpt starting mid-song | 0.5–2 s | 2–4 s |
| Podcast intro music under speech | 1–3 s | 3–5 s |
| Ending a full song | — | 5–10 s |
Short fades are about technical cleanliness: anything under about 50 ms isn't heard as a fade at all, just as a clean start or stop. Long fades are musical: they tell the listener the clip is ending on purpose. A ringtone sits in the middle — a fade out of one to two seconds keeps the loop smooth without wasting much of the 30 seconds you have.
For fade ins, be careful with anything rhythmic. A two-second fade in over a strong beat can make the first bar sound weak. If the excerpt starts on a downbeat, a very short fade (or none) often sounds better than a long one.
Linear, smooth and exponential curves
The curve describes how quickly the volume changes over the length of the fade. Our fade tool offers three:
- Linear changes the amplitude at a constant rate. It is simple and predictable, but because our hearing is roughly logarithmic, a linear fade out seems to hold up for a while and then drop away suddenly at the end.
- Smooth (a raised-cosine or "S" curve) starts slowly, moves fastest in the middle and eases into the end. There is no sudden corner at either edge, which makes it the best default for nearly everything.
- Exponential (here, a squared curve) stays close to silence at the start of a fade in and drops quickly at the start of a fade out, then tails off gently. It sounds natural on music with long sustained notes and on room ambience.
Audio engineers sometimes use equal-power curves for crossfades between two clips, so the combined loudness doesn't dip in the middle. For a single clip fading to or from silence, the smooth curve gives a similar perceived evenness.
Why fades remove clicks
When audio is cut at an arbitrary point, the waveform usually isn't at zero. Playback jumps instantly from silence to that value — a step that contains energy at all frequencies, heard as a click or pop. A fade forces the first and last samples to exactly zero and approaches the cut gradually, so there is no step.
The same thing happens when a ringtone or alarm loops: the last sample of the file jumps back to the first. If both ends are faded to silence, the join is clean. That is why every ringtone page on this site adds a fade by default.
Order of operations
Fades should be applied after volume changes and normalization. If you normalize after fading, the result is identical; but if you boost a clip after it was faded, any clipping limiter or compressor you use later can lift the faded ends back up. In this tool the order is fixed — trim, mix to mono if chosen, apply gain or normalize, then fade — so the ends of the exported clip always reach true silence.
If the fade in and fade out together are longer than the clip, both are shortened in proportion so they meet in the middle instead of overlapping.
Common mistakes
- Fading out over the hook. If the best moment of your ringtone is in the last two seconds, it will be faded away. Move the selection so the fade lands on a less important part.
- Fades that are too long for short clips. A three-second fade out on a five-second notification means most of it is quiet. Keep notification fades under half a second.
- No fade at all on speech edits. Even a cut in a silent gap can click if there's background noise. A 10 ms fade costs nothing.
- Judging by eye only. Turn on Loop and listen to the end and beginning together; that's how your ringtone or alarm will actually sound.
Try it
Open the fade in / fade out tool, load a file (or the built-in sample), and watch the dashed envelope line on the waveform as you move the sliders. Then switch curves while looping playback to hear the difference. Next, read how to cut an MP3 precisely or how to normalize audio.