Expand a Selection in Photoshop (and Resize It Precisely)
Whether you need to grow a selection slightly or reshape its outline, Photoshop gives you precise control. In this tutorial, you’ll learn how to transform the selection boundary itself and how to expand or contract it by a specific number of pixels. Follow along to clean up edges and fit selections perfectly to your subject.
Step-by-step instructions
Make an initial selection
Choose the Magic Wand Tool (W) or Quick Selection Tool (W).
Click and drag to select your subject; refine as needed until marching ants outline the area.
Confirm the correct layer is active in the Layers panel.
Transform the selection outline (not the image)
Right‑click inside the selection → Transform Selection.
Drag corner or edge handles to resize the selection boundary.
Hold Alt/Option while dragging to scale from the center proportionally.
Hold Ctrl/Cmd while dragging a handle to distort as needed.
Press Enter/Return to commit the transform.
Expand the selection by pixels
Go to Select → Modify → Expand…
Enter 2 px (or your desired amount) and click OK.
Check the edges; the marching ants will move outward.
Contract the selection if needed
Go to Select → Modify → Contract…
Enter 5 px (or your desired amount) and click OK.
Use this to pull the selection inward and avoid unwanted edges.
