Upload an audio file, then choose how long the fade‑in should last (0‑10 seconds).

Click or drag & drop an audio file here

How to Fade In Audio Online – Free Fade In Effect with Curve Control

Learn how to fade in audio online free. Add smooth volume increases with start time, duration (0-10s), and curve type (linear, logarithmic, exponential, sinusoidal). Perfect for podcast intros, music beginnings, and professional sound design. No signup.

How Does Advanced Fade‑In Work?

Fade‑in gradually increases volume from silence to original level over a specified duration, starting at any point in the audio. Our tool uses FFmpeg's afade filter with four curve types: Linear (steady rise), Logarithmic (fast then slow), Exponential (slow then fast), and Sinusoidal (S‑curve, most natural). This gives you full control over how the volume ramps up.

Step‑by‑Step to Add Advanced Fade‑In

1. Upload your audio file (MP3, WAV, FLAC, etc.).
2. The original audio preview appears with duration displayed.
3. Set start time and duration (seconds) using sliders.
4. (Optional) Expand advanced options to choose a curve type (Linear, Logarithmic, Exponential, Sinusoidal).
5. Click 'Apply Fade In' – preview and download the result in the original format.

Frequently Asked Questions

1. What is the difference between the four curve types?

Linear: volume increases at a constant rate. Logarithmic: volume rises quickly at first then slows – gives a sudden start. Exponential: volume starts slow then accelerates – smooth build‑up. Sinusoidal: S‑shape curve, most natural and gentle for music.

2. Can I fade in from the middle of the track?

Yes, the start time slider allows you to begin the fade‑in at any point (e.g., after an intro).

3. What is the maximum fade duration?

Fade duration is limited to 10 seconds or the remaining audio length, whichever is smaller. This prevents unrealistic long fades.

4. Is my audio uploaded to a server?

No. All processing happens locally in your browser using FFmpeg.wasm. Your files stay private.

5. Why does the output file size change?

Fade‑in does not significantly change file size, but re‑encoding may alter it slightly. Original format is preserved.

6. Which curve is best for podcasts?

Linear or Sinusoidal are recommended for natural, smooth starts. Exponential works well for dramatic intros.

Create Professional Audio Intros with Flexible Fade‑In

With advanced fade-in controls — start time, duration, and four curve types (linear, logarithmic, exponential, sinusoidal) — you can craft the perfect opening for any audio project. Perfect for podcasters, musicians, video editors, and sound designers. No signup, no watermarks, completely private.