Builds an ICO file at the one size you choose; for a multi-size favicon.ico, convert separately at each size you need.
Introduction
ICO is a container format built for icons, and it's capable of holding several sizes of the same image inside one file — a 16×16 version for a browser tab alongside a 256×256 version for a desktop shortcut, for example. This tool builds a single .ico file from a source image you upload — PNG, JPG, JPEG, or WEBP. This is a general-purpose icon-building utility rather than a classroom tool as such, though a teacher setting up a favicon for a class or department website would use it the same way any small site owner would. The one thing worth knowing before you start: this specific tool builds an ICO containing exactly one of those sizes — the one you pick — not a bundle of several. More on why that distinction matters below.
One Size Per ICO, Not a Multi-Size Bundle
Before converting, you choose a single target size from a list — 16×16, 24×24, 32×32, 48×48, 64×64, 96×96, 128×128, 192×192, or 256×256 pixels. That choice fully determines the resulting file: it will contain exactly one image, at that one size. This is worth being explicit about, because ICO as a format doesn't work that way by default. Microsoft's own documentation of the icon format describes an ICO file as starting with a directory that can list any number of images, each at its own size and color depth, so software can pick whichever one fits a given context. A typical favicon.ico bundles several sizes together for exactly that reason. This tool doesn't do that bundling: converting the same source image at 32×32 and then again at 256×256 gives you two separate single-size files, not one file containing both.
If your goal is a single icon for one specific use — a browser-tab favicon at 32×32, say — that's exactly what this tool produces. If you need a favicon.ico that covers several sizes at once, converting multiple times here won't merge the results into one multi-size file; each conversion stays a separate, single-size ICO.
How the Conversion Works
This tool accepts .png, .jpg, .jpeg, and .webp files, up to 15 MB. The source image is resized to your chosen target dimensions using a smoothed resampling method — it blends neighboring pixels rather than simply duplicating or dropping them — before being written into the ICO. That resampling can't invent detail that isn't present in the original: enlarging a small source image up to a large icon size (say, a 64×64 logo scaled up to 256×256) will look softer than a source that was already that large to begin with, not sharper. For the clearest result at a given size, start with a source image at least as large as your target.
Transparent backgrounds are preserved. If your source PNG or WEBP has a transparent background, that transparency carries through into the resulting ICO — useful since icons are typically displayed over varying backgrounds (a light browser tab, a dark taskbar, a colored desktop) rather than one fixed color.
Choosing a Source Image
Because the final icon may be displayed quite small, a source with simple shapes and strong contrast tends to hold up better after resizing than a busy photo or an image with fine detail and small text — that kind of detail is exactly what tends to blur or disappear once resampled down to something like 16×16 or 32×32. A square, or near-square, source also avoids the image being stretched or padded awkwardly to fit the target dimensions.
What to Check Before You Use the Result
- Each conversion produces one size, in one file. If you need several sizes, convert the source once per size and keep each resulting file — they won't combine into a single multi-size ICO automatically.
- A small source enlarged to a large size will look soft. Check the result at your intended display size before using it, especially if the target size you picked is larger than your original image.
- Only .png, .jpg, .jpeg, and .webp sources are accepted, up to 15 MB. To go the other direction — extracting every image already inside an existing ICO file — use Ico To PNG.
Example
A logo saved as a 512×512 PNG with a transparent background needs to become a browser-tab favicon. Converting it here at 32×32 produces a single ICO file at that size, with the transparent background intact, ready to reference from a site's favicon link. If a 16×16 version is also needed for a different context, that's a second, separate conversion at that size — not an additional size folded into the same file.
FAQs
What image files can I convert to ICO?
.png, .jpg, .jpeg, and .webp files, up to 15 MB.
Can I create an ICO with multiple sizes bundled together, like a typical favicon.ico?
No — each conversion produces one ICO file containing exactly one size, the one you selected. Converting the same image at different sizes gives you separate single-size files, not one combined multi-size ICO.
Why does my icon look blurry?
If the target size you picked is larger than your source image's actual dimensions, the image has to be enlarged, which softens fine detail rather than sharpening it. Start with a source image at least as large as your intended icon size for the clearest result.
Will my transparent background be preserved?
Yes, for PNG and WEBP sources with transparency. That transparency carries through into the resulting ICO file.
Is my file kept afterward?
No. Files are processed only to complete the conversion and are automatically deleted within 2 hours — see the Privacy Policy for details.
I have an ICO and need the images out of it — is there a tool for that?
Yes, see Ico To PNG.
