How to Draw a Perfect Circle in Paint.NET

Drawing a perfect circle in Paint.NET is a straightforward process whether you need to create a visible graphic or define an exact circular area to edit. By default, the ellipse tools produce freeform ovals, but you can instantly constrain the width-to-height ratio to 1:1 by holding down a single modifier key or adjusting the tool settings in the toolbar. This guide covers how to draw a solid or outlined circle using the Shapes tool and how to create a circular selection using the Ellipse Select tool.

Drawing a Circle with the Shapes Tool

To draw a visible circle on your canvas:

  1. Select the Shapes Tool: Click the Shapes icon in the Tools palette or press the keyboard shortcut O.
  2. Choose the Ellipse Shape: In the top toolbar, open the shape dropdown menu and choose the Ellipse option.
  3. Configure Style and Colors: Set your Primary and Secondary colors in the Colors palette. In the toolbar, adjust the brush width and choose your fill style (Draw Outline, Draw Filled Shape, or Draw Filled Shape with Outline).
  4. Draw the Circle: Click and drag on your canvas while holding down the Shift key. The Shift key locks the aspect ratio to a 1:1 ratio, forcing the ellipse to remain a perfect circle.
  5. Finalize the Placement: Release the mouse button first, then release the Shift key. While the bounding box is still active, you can click and drag the control nubs to scale the circle (continue holding Shift to preserve the shape) or drag the center to reposition it. Press Enter to commit the shape to the canvas.

Making a Perfect Circular Selection

If you want to cut, copy, or fill an exact circular region:

  1. Select the Ellipse Select Tool: Click the Ellipse Select tool in the Tools palette or press S until the ellipse selection icon is active.
  2. Hold Shift to Select: Click and drag across the canvas while holding down the Shift key. This constrains the selection boundary to a perfect circle. Release the mouse button before releasing the Shift key.
  3. Use Fixed Ratio (Alternative Method): In the top toolbar, locate the Normal dropdown menu and change it to Fixed Ratio. Ensure both the width and height values are set to 1. With this setting enabled, every ellipse selection you draw will automatically maintain a perfect circular proportion without needing to hold down the Shift key.