1Upload the ICO icons you want resized — work from the largest original you have rather than from a copy you already shrank once.
2Type a target width, a target height or a percentage, and leave the aspect-ratio lock on unless you deliberately want stretching.
3Run the resize; every file in the batch is taken to the same target in a single pass.
4Download the resized ICO file, or the whole set together as one archive.
Resize ICO FAQ
What dimensions should I actually target?
+
Match the slot it will live in. A full-width web hero rarely needs more than 1920 pixels wide, a content image 1200, a thumbnail 400, and doubling those numbers covers high-DPI screens. Anything beyond that is bytes nobody sees.
How does Resize ICO change the dimensions?
+
Concretely, the request is really about which sizes belong in the stack: entries are re-rendered at the standard 16, 32, 48, 64, 128 and 256 pixel steps rather than at an arbitrary dimension, because that is what Windows and browsers ask for. You give it a target width, a target height or a percentage, and it works from the original rather than from a previously resized copy.
Is there anything specific to ICO I should watch for?
+
Yes — an ICO is a stack of square bitmaps, not one image, so operations apply to the stack and Windows still picks whichever size it wants. Worth checking before you resize a file you will not be able to regenerate.
What is the most common mistake when resizing ICO icons?
+
Upscaling. Enlarging cannot invent detail that was never captured, so the result is a soft version of the original at a bigger size. Always resize down from the largest source you have, and resize once rather than in stages.
What can I upload to Resize ICO?
+
ICO files containing one or several sizes, plus ordinary PNG or JPG artwork if you are building an icon rather than editing one. Windows .ico and browser favicon files are the same format.
Is there a file size limit on Resize ICO?
+
Yes: free accounts process images up to 5 MB each, which no icon file will ever approach — a full 16-to-256-pixel stack is typically well under 200 KB. Icons are the one part of the image family where the cap is genuinely irrelevant.
Will Resize ICO lower the quality of my ICO icons?
+
The sizes stored inside an ICO are lossless bitmaps, so the pixels themselves do not degrade. What actually decides how good an icon looks is whether the size the operating system asks for exists in the stack — a 256 px entry downscaled on the fly by Windows always looks worse than a real 32 px entry.
Can I run Resize ICO on several ICO icons at once?
+
Yes. Icon files are tiny, so a batch of them completes almost instantly; the round trip is dominated by the upload, not the processing.
Why does a EPUB site host Resize ICO?
+
EPUB.to is built around the open eBook format — XHTML in a zip, reflowable by design, and readable on hardware nobody has thought about the layout for. A book is a zip full of markup, images and fonts, so almost every job people bring to an eBook site is really a job on one of those things. Resize ICO runs on the same upload and the same account as the conversions because that is where it is needed.
What should I do with the result once Resize ICO is finished?
+
The converter on this site moves books between EPUB, MOBI, AZW3, PDF and DOCX, so a title ends up on whatever hardware is actually going to read it. Doing that after Resize ICO means the conversion is made from the version you settled on, not from the one you were still fixing.
Is Resize ICO here the same tool the sibling sites run?
+
The engines are shared — the same toolchain, the same workers, the same limits. What a EPUB site adds is a view on reflow: which of these operations a reflowable book genuinely supports, and which ones only make sense on the fixed-layout media inside it. It also starts from one fact about the format this site is named after: the book is a zip of XHTML with a manifest, so the text costs almost nothing and every decision that matters is about the embedded images and font subsets.
Do I need an account, and does anything get kept?
+
No account, and nothing is kept: uploads are deleted from the workers shortly after the job finishes, nothing is read and nothing is indexed. Free accounts exist for history and batch size, not for access.
