Resize ICO File
Upload an ICO, choose the exact image sizes to keep or create, and download one rebuilt .ico file.
Drop your ICO here
or browse files
ICO • Max 10MB
Choose output sizes
The downloaded ICO will contain exactly these dimensions.
How it works
Rebuild the file, not only the preview
An ICO is a container. It can hold a 16x16 image for compact browser tabs, a 32x32 image for higher-density displays, and larger images for desktop shortcuts. Changing one embedded image does not automatically change the others.
The resizer decodes every image in your upload, chooses the largest embedded image as the source, scales it to each selected dimension, and packages those results into a new ICO. This avoids enlarging a 16x16 entry when the same file already contains a cleaner 64x64 or 256x256 source.
Which sizes to use
| Goal | Select | Why |
|---|---|---|
| Website favicon | 16, 32, 48 | Compact browser coverage without unused large entries. |
| Windows icon | 16, 24, 32, 48, 256 | Covers small UI controls through large icon views. |
| One fixed requirement | Requested size only | Produces the smallest file for a system that expects one dimension. |
Three common resize jobs
Remove oversized entries
Upload a 16, 32, 48, 256 ICO and select 16, 32, 48. The output keeps the web sizes and leaves out 256x256.
Add a missing browser size
Upload a 32x32 ICO and select 16, 32, 48. The tool creates all three entries from the 32x32 source and warns because 48x48 is an upscale.
Create a single-size ICO
Clear every option except 64x64. The downloaded file contains one 64x64 image rather than a multi-size bundle.
Quality limits
Downscaling starts from the largest embedded image, but tiny icon artwork can still lose thin lines or small text. Inspect the preview at the size where the icon will appear.
Upscaling cannot add detail. For a crisp 256x256 result, start with an ICO that already contains a large image, or return to the original vector or high-resolution raster artwork.
Need to edit the artwork first? Extract the source with ICO to PNG, make your changes, then use PNG to ICO.
Frequently Asked Questions
Can an ICO file contain more than one size?
Yes. One ICO can bundle several images. This tool rebuilds the file with exactly the square sizes you select.
Which ICO size should I choose?
For a website favicon, start with 16x16, 32x32, and 48x48. Add 256x256 when the file also needs a high-resolution Windows icon.
Will enlarging a small ICO make it sharper?
No. Upscaling changes the pixel dimensions but cannot restore missing detail. Start from a larger ICO, PNG, or SVG when sharp large output matters.
Does resizing preserve transparency?
Yes, when the selected source image contains transparency. The rebuilt ICO uses PNG image data for each output size.
Is my ICO uploaded?
Yes. The file is sent to our server for decoding and resizing. The tool processes it in memory and does not save it to persistent storage.
Why is 256x256 the largest option?
The ICO directory format represents image width and height with one byte, where zero denotes 256 pixels. Use PNG or SVG for larger standalone images.