--- title: "Audio Fade In and Out - Smooth Audio Online | CanDoYa" description: "Add an audio fade in and fade out online, preview the curve, and download a private WAV. Free, no sign-up, and your file is never uploaded." url: https://candoya.com/tools/fade-in-out/ locale: en type: browser-tool --- # Audio Fade In and Out Online Category: Social & Creator ## What does an audio fade in and fade out do? An audio fade in raises volume smoothly from silence at the start, while a fade out lowers it to silence at the end. Set each duration, choose a curve, preview the effect, and download a WAV. Processing stays in your browser, so the source audio is never uploaded. The preview changes playback volume in real time. Export loads a WebAssembly build of FFmpeg only when you create the result, applies the same fade settings to the audio samples, removes source metadata, and writes an uncompressed 16-bit WAV. Choose **smooth** for a natural musical envelope, **linear** for a constant amplitude change, or **exponential** for a more dramatic shape. Fade lengths stay inside the source duration and never overlap. ## How to use it 1. **Choose your audio** - Drop in a browser-supported MP3, WAV, M4A, AAC, FLAC, OGG, Opus, or WebM audio file. 2. **Set the fade lengths** - Adjust the fade in and fade out independently, or start with a quick cleanup, intro and outro, or long outro preset. 3. **Choose and preview the curve** - Pick smooth, linear, or exponential, then play the source to hear the selected volume envelope. 4. **Export the result** - Apply the fades locally, listen to the finished WAV, and download it to your device. ## Who it's for - **Podcast and interview editors** can soften the start of an intro and finish an outro without a hard stop. - **Musicians and producers** can polish demos, backing tracks, samples, and song endings before sharing them. - **Video creators** can prepare music beds and voice clips that enter or leave a scene cleanly. - **Ringtone and notification makers** can tame an abrupt first note or shorten a harsh tail. ## Expert note A 10 to 50 millisecond fade can suppress a click caused by cutting audio away from a zero crossing. For a musical ending, several seconds usually sounds more intentional; the quarter-sine curve keeps more perceived loudness through the middle than a linear amplitude ramp. ## Frequently asked questions ### Is my audio uploaded to add the fades? No. File selection, preview, fade processing, and WAV creation happen inside your browser tab. The first export downloads the FFmpeg engine code, but your recording is not sent with that request. Closing or refreshing the tab releases the temporary source and result URLs. ### Is this audio fade in and out tool free? Yes. You can preview, process, and download faded audio without an account, subscription, credit limit, or watermark. The practical limits come from your browser memory and device speed because the entire source and uncompressed WAV result must fit locally. ### What audio formats and limits are supported? The file picker accepts common audio formats including MP3, WAV, M4A, AAC, FLAC, OGG, Opus, and WebM. Your browser must read the duration for exact fade placement. The conservative size limit ranges from 100 MB on mobile or lower-memory devices to 250 MB on typical desktops. ### Which fade curve should I use? Use smooth quarter-sine for most music and speech because it tends to sound natural. Linear is useful for short technical fades and predictable amplitude changes. Exponential keeps the signal quieter for more of a fade in, or drops it faster during a fade out, creating a stronger effect. ### How long should an audio fade be? Use about 0.01 to 0.05 seconds to remove a click, 0.2 to 1 second to soften a clip edge, and 2 to 8 seconds for a song or podcast ending. The right duration depends on rhythm, speech cadence, and how quickly you want attention to shift. ### Does fading change audio length or pitch? No. A fade multiplies sample amplitude with a changing gain envelope. It does not trim, stretch, resample, or pitch-shift the source, so the result keeps the same duration and pitch. Only the loudness near the beginning and ending changes. ### Why does the download use WAV? The result is a 16-bit PCM WAV so the fade does not add another lossy compression pass. WAV files are larger than MP3 or AAC, but they are widely supported and suitable for further editing. Use an audio converter afterward if you need a smaller delivery format. ## Related tools - [Audio Trimmer](https://candoya.com/tools/audio-trimmer/) - [Audio Volume Changer](https://candoya.com/tools/volume-changer/) - [Ringtone Maker](https://candoya.com/tools/ringtone-maker/) - [Audio Normalizer](https://candoya.com/tools/audio-normalizer/) - [Audio Waveform Image](https://candoya.com/tools/audio-waveform-image/) --- *Markdown edition of , published for AI agents and other automated readers. Index of key pages: .*