EDIT
☞ runs entirely in your browser — nothing is uploadedDrop your image here
or click to browse — PNG, JPG, WebP or GIF
Preview
OneImageTool
Free Image Tools
EDIT
Rounded corners that are really transparent, not white squares pretending.
or click to browse — PNG, JPG, WebP or GIF
Preview
percent, not pixels
Forty pixels of corner radius is invisible on a 4000 pixel photo and swallows half a face on a 400 pixel avatar. That is why the radius here is a percentage of the shorter side: one setting looks the same on a thumbnail and on a poster. The pixel value it works out to is shown underneath, so you can still match a spec that asks for one.
The other half of the job is the format. Rounded corners need transparency, and JPEG has none — save a rounded image as JPEG and the four corners come back as solid black unless something fills them. This tool defaults to PNG, keeps the corners genuinely empty, and if you do pick JPEG it asks for a background colour instead of quietly producing black triangles.
three steps
PNG, JPG, WebP or GIF. It is decoded in the page and never uploaded.
Drag the slider from 0 to 50 percent of the shorter side. At 50 percent on a square image you get a circle. Add a border in the same panel if you want one.
PNG keeps the corners transparent. JPEG and WebP are there too, with a background colour for the parts the rounding cut away.
quick answers
In PNG and WebP, yes — the pixels outside the rounded path have an alpha of zero. In JPEG they cannot be: the format has no alpha channel at all, so you pick a background colour and the corners are filled with it.
Because a radius in pixels only makes sense at one image size. Ten percent looks the same on a 400 and a 4000 pixel image, while 40 pixels looks like nothing on one and like a circle on the other. The pixel equivalent is shown under the preview.
On a square image, set the radius to 50 percent. On a rectangle that gives a capsule shape instead — use the circle crop tool, which squares the image first.
Yes. The border sits outside the rounded edge and follows the same curve, with the inner radius reduced by the border width so both arcs stay concentric. Set the border to 0 percent if you only want the rounding.
Browsers have a maximum canvas area. If the result would exceed it, the export is scaled down to fit and the preview says so rather than handing you a blank file.
No. The image is decoded, drawn and re-encoded in your browser. Nothing is sent to a server at any point.