Audio Fade In / Fade Out — Free Online

Hard starts and hard stops in audio files sound abrupt and unprofessional. A fade-in eases the listener into the content; a fade-out provides a graceful ending. Whether you are preparing a music track, a podcast intro, or a background audio loop, adding fades is one of the simplest and most impactful finishing touches you can apply to an audio file.

This tool adds configurable fade-in and fade-out envelopes to any audio file. Specify the duration of each fade independently, preview the result, and download the processed file. It works on all common audio formats and processes everything in your browser without any upload.

How to Add Fade In/Out to Audio Online

1. 1

   Upload your audio file

   Drop any MP3, WAV, FLAC, OGG, or AAC file. Files up to 100 MB are supported.

2. 2

   Set fade in and fade out duration

   Enter the fade-in duration (in seconds) at the start and the fade-out duration at the end.

3. 3

   Download your audio with fades

   Click Apply. FileCrank adds smooth fades and exports your audio. Files are deleted within 1 hour.

How Audio Fade Envelopes Work

A fade effect is implemented by multiplying each sample in the audio stream by a gain envelope — a curve that rises from 0 to 1 over the fade-in duration and falls from 1 to 0 over the fade-out duration. The shape of the curve matters: a linear fade sounds unnatural because human loudness perception is logarithmic. A logarithmic or equal-power curve is used instead, where the gain follows a sine or cosine function that corresponds to a perceptually even loudness change.

The tool applies the fade envelope using WebAssembly FFmpeg's afade filter, which supports linear, quarter-sine, half-sine, logarithmic, and exponential curves. The default is a logarithmic curve, which produces the most natural-sounding fade on most content.

Why Use FileCrank to Add Fades?

• ✓ Add fade in, fade out, or both in one step.
• ✓ Adjustable fade duration in seconds.
• ✓ Supports MP3, WAV, FLAC, OGG, and AAC input.
• ✓ No watermarks, no signup, completely free.
• ✓ Files are processed securely and deleted within 1 hour.

תכונות ומפרטים

גודל קובץ מקסימלי

עד 100 MB

פרטיות

הקבצים נמחקים לאחר כשעה

מחיר

חינם, ללא הרשמה

עיבוד

בשרת

Frequently Asked Questions

Dedicated Fade Tool vs Manual Envelope in a DAW

Drawing fade envelopes manually in a DAW is precise but requires loading the file into a project and exporting. For a simple fade-in and fade-out with no other editing needed, that overhead is unnecessary. This tool applies the fade and exports the file in a single step from the browser, making it the fastest option for adding fades to a finished file.

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