Rounded Corners takes a card image (or batch of card images) and rounds the corners by a configurable radius. The output is a transparent PNG, useful for clean print-and-play, mockups, or sell-sheet hero shots.

What this page helps you do

Round the corners of one image or a batch.
Match a specific corner radius (3 mm is common for cards).
Get a transparent PNG that drops cleanly into other tools.

Open the tool

Tools → Prototyping (or Designing) → Rounded Corners.

Upload images

Drag in or upload one or many card images. PNG and JPG are supported.

Set the radius

Pick a corner radius:

In mm if you also enter the card's physical size (most accurate for matching real cards).
In pixels if you want pixel-precise corners regardless of physical size.

The standard for board game cards is around 3 mm radius. Eyeball it against an existing card you like.

The preview shows what one image looks like with the rounding applied.

Export

Click Process all (for batches) or Process (for one). The tool outputs each image as a transparent PNG with rounded corners.

Download as a zip for batches.

Tips & common questions

Why transparent PNG? Rounding corners means the corner area becomes empty. PNG with transparency preserves the empty area cleanly. JPG can't represent transparency.

My corners look jagged. Use a higher resolution source. The tool anti-aliases corners automatically, but at low resolution there's not much room.

Can I round corners and add a stroke / border? Today the tool just rounds. For borders, run the rounded image through your design tool and add a stroke layer.

Why does this matter? Square-cornered cards look prototypey. Rounded corners signal "this is a real card." For mockups going into pitches or sell sheets, the visual polish helps.