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ICO to WebP converter

Convert ICO images to WEBP format

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

WebP keeps the one thing that matters most about an icon, its transparency, and it will not wreck the edges the way JPEG does. What it will not do here is stay lossless, since a browser canvas exposes only the lossy WebP path. At icon dimensions the byte savings that make WebP attractive for photographs mostly evaporate. This pair earns its place when you are standardising a mixed folder of site assets on WebP, not when you want the smallest or sharpest possible icon.

Key facts about ICO to WebP converter

Key facts about ICO to WebP converter
Encoding modeLossy VP8 with alpha. The lossless WebP variant, which would suit flat icon artwork perfectly, is not reachable from canvas.toBlob.
TransparencyKept. WebP stores alpha in a separate ALPH chunk, so a 32-bit icon entry or a one-bit mask both give a transparent background.
Quality controlA slider from 30 to 100 in steps of 5, starting at 90, sent straight to the encoder with an estimated size beside it.
Edge behaviourBetter than JPEG, worse than PNG. VP8 subsamples chroma, so saturated icon colours fringe along hard boundaries below about quality 80.
Size at icon dimensionsA 32x32 icon usually gives 300 bytes to 1 KB. RIFF container overhead is a meaningful share of that, so the win over PNG is small or absent.
Source entryOne image only. A multi-size container is decoded by the browser into a single picture, with no control over which entry that is.
ScalingThe resize presets shrink but never enlarge, so a 16-pixel icon cannot be turned into a 64-pixel WebP here.
Opens the resultChrome, Edge, Firefox and Opera, Safari from 14, Windows 10 onward, macOS Big Sur onward, plus GIMP and Affinity.

What happens to your file

This runs entirely in your browser with no network involvement. The icon is exposed through an object URL, decoded by the icon parser built into the browser, and drawn into a canvas belonging to this tab. Asking that canvas for image/webp calls the browser's own encoder on your machine. There is no upload request in the conversion path and no back end behind this page to receive one.

About this tool

  1. 1

    Add your icons

    Drop up to twenty .ico files onto the target area, or click it to open the picker.

  2. 2

    Check what was decoded

    The preview shows the entry your browser chose, over a checkerboard so you can see the transparency that will be preserved.

  3. 3

    Keep quality high

    At icon sizes the file is tiny regardless, so leave the slider at 90 or push it to 100.

  4. 4

    Convert and save

    Press Convert, then download the WebP or take converted-webp-files.zip, assembled locally for multi-file runs.

Specs & compatibility
Input and outputTakes .ico only (image/x-icon) and returns .webp with the image/webp type; any other extension is refused before decoding.
Conversion pathICO to WEBP runs in three steps: an <img> element decodes the icon and the browser picks one entry from a multi-size file; the pixels land on a 2D canvas in this tab; then canvas.toBlob with the image/webp type returns the finished file.
Browser supportThe icon side decodes in Chrome, Edge, Firefox and Safari, while writing the WebP works in Chromium browsers and Firefox, and where the type is unsupported the canvas specification makes the browser return PNG bytes under the .webp name.
Controls for this pairA 30 to 100 quality slider (steps of five, default 90) drives the WEBP encode, max-dimension presets from 3840 down to 200 px resize the ICO first, and the strip-metadata toggle is moot on this pair.
Batch, caps and namingTwenty ICO files per run at 500 MB each; one result downloads as a single WEBP, several as converted-webp-files.zip, zipped by JSZip 3.10 in page memory.
Device ceilingThe canvas caps it: past roughly 16,384 px a side Chromium refuses the bitmap and iPhone Safari gives up sooner, so an oversized ICO fails before any WEBP bytes exist.
  • Compare the output against a PNG of the same icon; at these dimensions PNG is lossless and frequently smaller.
  • Keep the original .ico if Windows or a favicon route references it, because WebP cannot take over those jobs.
  • Standardising a site asset folder on one format is the real reason to use this pair, not chasing kilobytes.
  • Quality below 80 shows colour fringing on the hard outlines icon artwork is made of, so treat 80 as the floor.
  • Alpha channel carried through to WebP
  • Adjustable quality with an output estimate
  • Single-entry decode from icon containers
  • Twenty-icon batches bundled without a server
  • Normalising a mixed folder of site graphics onto one delivery format.
  • Putting an application icon into a web build whose asset pipeline standardises on WebP.
  • Producing a small transparent image of an icon for a documentation page or component library.
No. WebP defines a lossless mode that would be ideal for flat icon artwork, but browsers do not expose it through canvas.toBlob, the only encoder a page can reach without shipping a WebAssembly codec. Everything here is lossy VP8, even at quality 100. Convert to PNG for exact pixels.
Smaller than the icon, usually, since a raw icon payload is uncompressed. Against PNG it is a coin toss at these dimensions: a 32 by 32 icon gives a few hundred bytes to a kilobyte either way, and WebP carries fixed RIFF and alpha chunk overhead that matters when the image is this small.
Yes. Icon entries store transparency either as a full alpha byte per pixel or as a one-bit AND mask, and the browser resolves both into canvas alpha. WebP has a real alpha channel in its ALPH chunk, so you get a transparent WebP rather than a white or black square.
Not reliably. Browsers look for favicon.ico at the site root and accept PNG, GIF and SVG through link tags, but WebP favicons are inconsistently supported. Keep an .ico or PNG for that role.
Whichever the browser decoder hands over, and the page has no say. Chrome, Firefox and Safari each have their own selection logic, so the same icon can give different dimensions on different machines. Extract the entry you want with an icon editor first if it matters.

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