Audio Tools New Tool

Free Online Audio Fade In and Fade Out Tool

Add a fade in and a fade out to audio free, without uploading anything. Four real curve shapes, including the equal power law mixing desks use, and the closing fade is measured from each file's own real length, so a folder of different lengths all end correctly rather than halfway through.

Free Forever Nothing Uploaded Four Curve Shapes A Folder At A Time

Free Online Audio Fade In and Fade Out Tool

Advertisement Slot (Top Banner) Google AdSense Unit • Responsive Banner

Drop audio files here to fade them in and out A clean opening and a clean ending, with the curve you choose. As many files as you like. Select Audio Files MP3, WAV, M4A, OGG, FLAC and more • best under 25 minutes • nothing is uploaded

The shape of the file appears here, with the two fades shaded on it.

0:00.000 / 0:00

The two fades

Fade in2.0s How long the opening takes to arrive. Zero switches it off.

Fade out3.0s This one finishes exactly on the last sample, so there is no silent tail.

The shape of the fade

Curve

Output

Format

Bitrate

Sample rate

Channels

WAV detail Only used when the output is WAV. The compressed formats have their own.

Encoder

File name

.mp3

Buy Us A Coffee

Enjoying WizTools123? Help keep our server infrastructure 100% free and open for everyone.

Buy Us A Coffee

Sponsored Content (Below Tool) Google AdSense Placement

How to Fade Audio In and Out

Set the two lengths, pick a curve, run it.

Drop the file or folder in Every file keeps its own length, so the closing fade lands on each one's real ending rather than on an assumed one.

Set the two lengths Two seconds in and three out suits most music. Half a second each is usually right for speech. Either can be zero.

Choose the shape Equal power is the safe default. Exponential is the most natural for a music fade out. The small picture next to it shows exactly what you have chosen.

Run it and take the files The fades are shaded on the waveform before anything happens, so you can see where they sit.

Why the Shape of a Fade Matters

The part that makes a linear fade sound wrong.

A straight line does not sound straight. Hearing works on a ratio scale, so a fade that drops evenly in amplitude seems to hang around and then disappear suddenly at the end. That is why mixing desks use a curved law and why it is the default here.

The fade out is measured from the real end of each file. It is not a length the player counts back: the samples themselves are written quieter. In a batch every file has its own length, so every fade out lands correctly on its own ending.

The two fades cannot overlap. If they add up to more than the file lasts, the middle never reaches full volume. When that happens this page scales both down to fit and tells you, rather than producing something quietly wrong.

This cannot be undone. The quieter samples are written as quieter samples. Keep the original if you might want a different length later, and fade last: trimming afterwards puts the fade in the wrong place.

The work happens on your own machine. Your file is opened by this page, not sent anywhere. That is why there is no upload bar, no queue and no waiting for a server. It is also why a long recording leans on your own memory: nothing is being done for you somewhere else.

Most of what this page does needs no download at all. Your browser already has a full audio engine in it, and that is what does the work. A thirty megabyte encoder is only fetched if you ask for MP3, M4A, OGG or FLAC at the end. Ask for WAV and nothing is downloaded, ever.

MP3, M4A, OGG and Opus throw information away, every time. Opening one and saving it again is a second pass of that, so the result is always slightly worse than the original even if you changed nothing. Where it matters, take WAV or FLAC out of this page instead.

Leave the tab open. All of the work is in this page, so closing it or navigating away stops the job halfway. On a phone, switching apps can do the same thing, because the system is allowed to pause a background tab.

Key Features & Capabilities

What this tool does, and what it deliberately does not.

Nothing uploaded Everything happens in the page, on your own machine.

Four real curves Equal power, linear, exponential and S-curve, each drawn on the page so you can see what you picked.

Lands on the real ending The fade out is measured from each file's own length, which is what makes it work across a mixed batch.

Visible before it runs Both fades are shaded on the waveform, so an overlap or a fade that is far too long is obvious first.

A whole folder at once The same treatment across a set of clips, or per file settings when one needs to differ.

WAV downloads nothing Fading needs no encoder at all. One is fetched only for the compressed formats.

About the Bulk Audio Fade In and Out

A fade seems like the simplest possible edit and hides a small piece of psychoacoustics. The obvious implementation is a straight line: multiply the first second of samples by a value climbing evenly from nought to one. Do that and listen, and the fade in feels as if it starts too suddenly and the fade out seems to hang on and then disappear all at once. Nothing is wrong with the arithmetic. The problem is that hearing responds to ratios rather than to differences, so an even drop in amplitude is not an even drop in perceived loudness.

That is why mixing desks have never used a straight line, and why the default here is an equal power curve, which follows a cosine and keeps the perceived level moving smoothly. Exponential falls fast and then tails away, which is the shape most music fade outs actually have. An S-curve is gentle at both ends and suits a long fade where you do not want a noticeable start. All four are on the page, and the small picture beside the control draws the one you have chosen, because describing a curve in words is much less useful than showing it.

The practical trap is the fade out rather than the fade in. A fade in starts at zero seconds, which is easy. A fade out has to start at the length of the file minus the length of the fade, which means the file's length has to be known exactly. If it is wrong, the fade lands in the middle or does not happen at all, and nothing reports an error: the file simply comes out wrong. Here the length comes from the decoded audio rather than from anything typed on the page, and in a batch every file is measured on its own, which is what makes a folder of different lengths all end correctly.

The other trap is asking for more fade than there is file. Two three second fades on a four second clip would overlap, and the middle would never reach full volume. Rather than doing that silently, this page scales both fades down so they just meet and says so.

None of it can be undone afterwards, because the quieter samples are written as quieter samples and there is no record of what they were. That also means the order of operations matters: fade last. Trimming a file after fading it moves the ending away from where the fade was placed, and the result is a clip that fades to silence and then carries on.

Frequently Asked Questions

Lengths, curves, batches and what cannot be undone.

Drop it here, set the fade out length, and press the button. The fade is measured from the real end of your file, so it finishes exactly on the last sample with no silent tail left over.

For music, two seconds in and three out is a common choice and rarely sounds wrong. For speech, half a second at each end is plenty and anything longer sounds like a mistake. A fade that is a large share of a short clip always sounds deliberate, for better or worse.

A straight line drops evenly in amplitude, which your ear hears as hanging on and then vanishing. Equal power follows a cosine and is what mixing desks use. Exponential falls quickly and then tails off, which is the most natural shape for a music fade out. An S-curve is soft at both ends and suits long fades.

Yes. Set the other one to zero. Fading only the end is the most common single case, and there is a preset button for it.

They would overlap and the middle would never reach full volume. Rather than producing that quietly, this page scales both fades down proportionally so they just meet, and tells you it did.

No. The quieter samples are written as quieter samples, and there is no record of what they were. Keep your original, and do any trimming before fading rather than after, since trimming afterwards moves the ending away from where the fade was placed.