Round the corners of an image — smooth, transparent corners

How to use Round Corners

1. Choose one or more images.
2. Set Corner radius (% of the short side) from 1% to 50%. The default is 8%.
3. Keep Save as on PNG (the default) so the corners stay transparent.
4. Press Apply and download the result.

What it does and when to use it

Rounded corners make a screenshot, product photo or card image look softer and more finished. They are common for app screenshots in slides, thumbnails on web pages, profile banners, and images pasted into documents or emails where you cannot use CSS border-radius.

Small radii (3–10%) give a gentle card look. Around 20% gives a rounded-square, icon-like shape on a square image. At 50% the shorter sides become full half-circles, a pill or capsule shape.

For a fully round crop, use Circle Crop. To give the image room before rounding, add a margin with Image Padding. For a frame, try Image Border.

How it works

The radius in pixels is:

radius = shorter side × percentage ÷ 100

For pixels inside each corner square, the tool measures their distance from the corner’s centre point. Pixels well inside the curve keep full opacity; pixels outside become fully transparent. Pixels on the curve get partial opacity based on how much of the pixel the curve covers. That partial coverage is what makes the edge smooth instead of jagged. The rest of the image is not touched, and the colours are not changed. The image is processed in a background worker in your browser, so it is never uploaded.

Worked examples

These sizes follow the radius rule above.

• A 1200 × 800 screenshot at the default 8%. The shorter side is 800, so each corner has a 64 px radius. The image stays 1200 × 800, with transparent corners.
• A 1080 × 1080 square at 22%. Radius 237.6 px, a soft rounded-square look.
• A 1200 × 800 banner at 50%. Radius 400 px. The left and right ends become half-circles and the image becomes a pill shape.

Limits and tips

• The image size does not change; corners are cut away, not added.
• If you need a background colour behind the rounded corners rather than transparency, pick JPEG: the corners fill with white.
• On a dark page, white edge pixels from the original photo can show as a light rim. Crop a few pixels first if that happens.