↳ Your files stay in your browser.
Not a byte is uploaded to any server.
One multi-size ICO per image. Single sizes available too.
A little image.
A proper icon.
WebP supports full alpha transparency, unlike JPG. The question is whether that alpha survives the trip into an ICO file. We drew one 256 × 256 image with a rounded red square on a fully transparent background, saved it as WebP, then converted it through this tool at five sizes. Every pixel was counted.
Measurements checked 2026-11-02. The source is a 256 × 256 RGBA image: a red rounded rectangle (192 × 192, corner radius 48) with a yellow circle (radius 60) at the center. The exterior is fully transparent (alpha = 0). The source was saved as WebP at quality 90, then each ICO frame was rendered by the same browser canvas pipeline used by this converter. ICO bytes are the complete file including the 6-byte header and 16-byte directory entry per frame. PNG bytes are the embedded payload only. Corner alpha is reported for all four corners (top-left, top-right, bottom-left, bottom-right).
| ICO size | ICO bytes | PNG payload bytes | Transparent pixels | Opaque pixels | Partially transparent | Corner alpha (4 corners) |
|---|---|---|---|---|---|---|
| 16 × 16 | 656 | 634 | 60 | 68 | 128 | 0, 0, 0, 0 |
| 32 × 32 | 1,292 | 1,270 | 305 | 416 | 303 | 0, 0, 0, 0 |
| 48 × 48 | 1,879 | 1,857 | 826 | 1,040 | 438 | 0, 0, 0, 0 |
| 64 × 64 | 2,529 | 2,507 | 1,578 | 1,928 | 590 | 0, 0, 0, 0 |
| 128 × 128 | 4,773 | 4,751 | 6,975 | 8,220 | 1,189 | 0, 0, 0, 0 |
Every frame at every size has corner alpha of exactly 0. The transparent exterior of the WebP is preserved in the ICO. This is the key difference from a JPG source, where every pixel is opaque and corners would be white. The partially transparent pixel count represents anti-aliasing along the rounded edges — pixels where the vector curve meets the pixel grid and the renderer assigns partial coverage.
Download WebP source · 16px ICO · 32px ICO · 48px ICO · Measurement record
To reproduce: download the WebP source above, open it in this converter, select the sizes you want, and convert. Compare your output with the measurement record. The WebP file is 2,556 bytes and self-contained.
Yes. WebP stores a full 8-bit alpha channel, and the ICO format embeds each frame as a PNG with RGBA data. Our measurement confirms every corner pixel at every size has alpha zero. The transparent exterior of your WebP becomes the transparent exterior of your ICO. No white fill, no flatten.
The default is 16, 32 and 48 — the three sizes Windows uses most. Select 64, 96, 128 or 256 if your destination uses larger icons. A multi-size ICO contains all selected sizes in one file. You can also download a single size separately.
JPG has no alpha channel. Every pixel in a JPG is opaque, so a rounded icon saved as JPG gets white corners. WebP carries transparency, so the same icon saved as WebP keeps its transparent exterior. When both are converted to ICO, the WebP source produces an icon with real transparent corners. The JPG source produces an icon with white corners baked in.
Yes. This page reads your WebP with browser APIs. Rasterization and ICO packaging happen on your device. There are no image upload endpoints or server conversion steps.
Yes. WebP supports full alpha transparency. The converter renders each frame to a transparent PNG canvas and embeds it in the ICO. Alpha values are preserved. Our measured test confirms corner alpha of 0 at all sizes from 16 to 128.
They are the same thing. ICO is the file format Windows uses for icons. "WebP to icon" and "convert WebP to ICO" describe the same conversion. This tool produces a standard ICO file with PNG-encoded frames.
Select from 16, 24, 32, 48, 64, 96, 128 and 256 pixels. Each ICO contains exactly the sizes you select, with PNG-encoded image entries for Windows Vista and later.
No. This tool takes a single static WebP image. Animated WebP files are not supported. Use the first frame or a static WebP export.
This page accepts WebP, PNG, JPG and self-contained SVG. For JPG sources, see our JPG to ICO page. For PNG, use the main PNG to ICO converter.
Last updated: 2026-11-02. Measurements apply to the source-transparent.webp fixture documented above.
