Calculator
What the Round Image Corners does
Round Image Corners: clips the image to a rounded rectangle. Everything runs in your browser and the file is never uploaded.
Drop in a file and the Round Image Corners handles it locally. The work happens inside your browser tab, so there is no upload to wait for and no queue.
Typical users are anyone shrinking a photo before uploading it. Oversized images are the most common reason a page feels slow.
The page holds your values in memory and forgets them the moment you close it.
Each field is explained further down, along with the method and a worked example that uses the default values.
What do the Round Image Corners fields mean?
The Round Image Corners uses 4 inputs. Sensible defaults are loaded up front, which means you can change one number at a time instead of filling the whole form first.
| Field | What to enter | Default |
|---|---|---|
| Image file | stays on your device | none |
| Corner radius | accepts 0 to 50 | 10 |
| Radius unit | choose from % of the shorter side or pixels | % of the shorter side |
| Behind the corners | choose from Transparent (PNG), White or Black | Transparent (PNG) |
How does the Round Image Corners work?
Each output is derived from the inputs above in a single pass; there is no hidden state carried between runs, so the same inputs always give the same calculation.
Bad input produces an error, never a confident-looking wrong answer.
What a typical run looks like
You provide: Image file, Corner radius, Radius unit and Behind the corners
What happens: the file is read into memory by your browser, processed locally, and offered back as a download. It is never uploaded.
You get back: a new file plus a brief account of what happened to it, shown in the panel.
How long this takes is a property of your computer, not of our infrastructure, and file size is bounded by browser memory.
How to use it
- Choose your file under Image file, or drag it onto the drop area.
- Put Corner radius (0 to 50).
- Pick a value for Radius unit: the options are % of the shorter side or pixels.
- Pick a value for Behind the corners: the options are Transparent (PNG), White or Black.
- Press Round Corners.
- Check Status on the right.
- Print gives a tidy version without the navigation, which is handy for attaching to a file.
What this tool does not do
- Re-encoding a lossy format such as JPEG always loses some detail, even at maximum quality.
- EXIF metadata may be dropped during processing, which is usually desirable but worth knowing.
- Batch work is not supported; each run handles one set of values.
- The result inherits any error in the inputs without flagging it.
- Large files are limited by your available memory, not by an upload quota.
Frequently asked questions
You need Image file, Corner radius, Radius unit and Behind the corners. Nothing starts empty, so you can change one value at a time and watch how the result responds.
Corner radius accepts 0 to 50. Go outside it and you get an error against that specific field instead of a misleading number.
No upload takes place. The file is handled entirely in the browser and discarded when you close the tab.
No payment and no login. Advertising covers the running costs.
The computation is exact; how much you should trust the answer depends on how good your inputs are.