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Audio fade in and fade out online

Add smooth fade in and fade out effects with customizable curve types, visual waveform preview, and crossfade support.

Free & unlimited
Mode
All processing happens in your browser. No data is sent to any server.

Add a fade to the start or end of a file, or crossfade two files into one. The fades are real gain automation, not a volume multiplier applied afterwards: the page schedules ramps on a GainNode inside an OfflineAudioContext and renders the whole track through it. Four curve shapes are available and they behave differently. Linear ramps at a constant rate. Exponential starts slow and accelerates. Logarithmic drops fast then eases out. The S-curve is built from a cosine shape and is the one that sounds most natural on music, because it avoids the abrupt corners at the beginning and end of the fade. Crossfade mode takes a second file, overlaps the two by the length you choose, and fades one out as the other comes in.

Key facts about Audio fade in and fade out online

Key facts about Audio fade in and fade out online
MechanismGainNode automation inside an OfflineAudioContext — linear and exponential ramps for those curves, 100 stepped values for logarithmic and S-curve
CurvesLinear (constant rate), exponential (slow then fast), logarithmic (fast then slow), S-curve (cosine, smooth at both ends)
ModesFade a single file, or crossfade two files into one continuous track
PresetsQuick fade 0.5 s linear, song intro 3 s exponential, song outro 5 s logarithmic, crossfade-ready 2 s S-curve, podcast 1 s in / 1.5 s out S-curve, cinematic 4 s in / 6 s out exponential
Crossfade default3 seconds of overlap using the S-curve
Curve previewEach curve is drawn as a small SVG so you can see the shape before applying it
Exponential floorExponential ramps cannot reach true zero, so the curve bottoms out at 0.001 rather than silence
Output16-bit PCM WAV at the source's sample rate and channel count
Accepted inputMP3, WAV, OGG, FLAC, AAC and M4A, up to 500 MB per file

What happens to your file

Nothing is uploaded and no engine is fetched. Both files, if you use crossfade mode, are read into ArrayBuffers in this tab, decoded by the browser's own decodeAudioData, rendered through an OfflineAudioContext on your CPU, and written back to a 16-bit WAV by JavaScript on this page. There is no network request in the whole path once the page has loaded. The result lives as a blob: URL in your own tab's memory until you download it and is released when the page closes.

About this tool

  1. 1

    Choose the mode

    Fade for a single file's start and end, or crossfade to blend two files into one. Crossfade mode shows a second drop zone.

  2. 2

    Load your audio

    MP3, WAV, OGG, FLAC, AAC or M4A up to 500 MB per file. The page decodes and shows duration for each.

  3. 3

    Set the lengths

    Fade in and fade out are independent. A half-second fade is a click fix; three to five seconds is a musical fade; anything longer is a deliberate effect.

  4. 4

    Pick a curve

    Use the inline curve previews. S-curve for music, linear for short technical fades, logarithmic for an outro that drops away quickly, exponential for a slow dramatic entrance.

  5. 5

    Or use a preset

    Quick fade, song intro, song outro, crossfade-ready, podcast and cinematic each set both lengths and the curve in one tap.

  6. 6

    Render and download

    The whole file is rendered through the gain automation in one pass and comes back as a WAV.

Specs & compatibility
Input formatsMP3, WAV, OGG, FLAC, AAC, M4A
Maximum file size500 MB per file
Output format16-bit PCM WAV
Fade lengthsFrom half a second in the quick preset to six seconds in the cinematic preset, adjustable in between
Crossfade output lengthThe two durations added together, minus the overlap you choose
Curve resolutionLogarithmic and S-curve are approximated with 100 linear segments, which is far finer than the ear can resolve
BrowsersChrome, Edge, Firefox and Safari 14.1+ — Web Audio only
SpeedOffline rendering is much faster than real time; a full track renders in a second or two
  • A fade of 10 to 30 milliseconds is the standard cure for a click at a hard edit point, and it is far too short to hear as a fade.
  • S-curve is the safe default for music. Linear fades have audible corners at the top and bottom of the ramp on sustained material.
  • Logarithmic outros drop quickly and then hang, which is why they suit songs ending on a sustained chord.
  • For a crossfade, both tracks should be at similar loudness first — otherwise the overlap has an obvious dip or bump. Normalize them before crossfading.
  • Three seconds is a good crossfade default. Under one second it reads as a cut, over five it turns into a mash-up.
  • Exponential ramps in Web Audio cannot reach absolute zero, so an exponential fade-out ends a hair above silence. On anything with a noise floor this is inaudible.
  • If you only need to cut a file and avoid a click, the audio trimmer applies a fade at the cut point during export.
  • Fade in and fade out with independent lengths
  • Crossfade mode merging two files into one
  • Four curve shapes with inline SVG previews
  • Six presets from quick click-fix to cinematic
  • Real gain automation rendered offline
  • 16-bit WAV output at the source sample rate
  • Adding a professional three-second fade-out to the end of a song
  • Fixing the click at the start of a clip cut out of a longer recording
  • Crossfading two takes of a podcast intro into one continuous file
  • Building a seamless loop by crossfading the end of a track back into its start
  • Fading a music bed in under a voiceover without opening a DAW
  • Giving a cinematic trailer audio bed a long, slow entrance
S-curve for most music: it eases in and out at both ends, so there is no audible corner where the fade starts or stops. Linear for very short technical fades, where the shape does not matter and predictability does. Logarithmic for an outro that should drop away quickly and then taper — good for songs ending on a sustained chord. Exponential for a slow, dramatic build, since it stays quiet for most of the fade and then rushes up at the end. The inline previews show each shape before you commit.
It depends entirely on the job. Ten to thirty milliseconds is a click fix, inaudible as a fade, and is what you want at an edit point. Half a second to one second reads as a deliberate but brisk transition, which suits podcast intros. Three to five seconds is the classic song fade-out. Beyond that you are making an effect rather than a transition — the cinematic preset's six-second fade-out is long enough that the listener notices the fading itself as part of the piece.
You load two files and choose an overlap length. The tool renders both into one buffer, starting the second file so that it overlaps the tail of the first by that many seconds, and applies a fade-out to one and a fade-in to the other across the overlap using the curve you picked. The output length is the two durations added together minus the overlap. For it to sound right the two tracks should be at similar loudness; normalize them first if one is noticeably hotter.
A fade necessarily changes the samples, so it cannot be a lossless operation in the way a stream-copy trim can. What it does not do is add compression damage: the output is 16-bit WAV, so there is no lossy re-encode in this step. If your source is an MP3 it is decoded once to apply the fade and the result is written uncompressed, which means the only quality change is the fade itself plus 16-bit quantisation. Encode back to MP3 once afterwards if you need a small file.
Because the Web Audio exponential ramp is mathematically unable to reach zero — an exponential curve approaches silence asymptotically but never arrives. The implementation clamps the floor at 0.001 of full scale, which is about -60 dB. On any real recording that is well below the noise floor and inaudible. If you need a mathematically exact silence at the end of the file, use the linear or S-curve option, both of which are built from ramps that do reach zero.
No. The tool uses only the Web Audio API in your browser: files are decoded in the tab with decodeAudioData, rendered through gain automation in an OfflineAudioContext on your own CPU, and written back to WAV by JavaScript on this page. Unlike the converter tools here it does not even download a processing engine, so after the page loads there is no network request at all. The result is a blob: URL pointing at memory in your tab, released when you close it.

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