How to Make a Square Selection in Photoshop

Creating a perfect square selection in Adobe Photoshop is a fundamental skill for photo editing, cropping, and graphic design. This guide explains how to constrain the Rectangular Marquee Tool to a 1:1 aspect ratio using simple keyboard shortcuts as well as the tool’s built-in options bar for exact dimensions.

Method 1: The Shift Key Shortcut (Fastest)

The quickest way to draw a square is using the Shift modifier key:

  1. Select the Rectangular Marquee Tool from the Tools panel on the left, or press the shortcut key M.
  2. Click anywhere on your canvas to set the starting corner of your selection.
  3. Hold down the Shift key on your keyboard.
  4. Drag your cursor diagonally to expand the selection box; it will automatically constrain to a 1:1 square aspect ratio.
  5. Release the mouse button first, and then release the Shift key. If you release the Shift key before releasing the mouse button, the selection will revert to a freeform rectangle.

Tip: To expand the square outward from its center point rather than from a corner, hold down Shift + Alt (Windows) or Shift + Option (macOS) while dragging.

Method 2: Setting a Fixed Ratio in the Options Bar

If you prefer to draw squares without holding down keys:

  1. Choose the Rectangular Marquee Tool (M).
  2. Look at the Options bar running along the top of the workspace.
  3. Locate the Style dropdown menu (set to "Normal" by default) and select Fixed Ratio.
  4. Set the Width to 1 and the Height to 1.
  5. Click and drag anywhere on your canvas. Every selection you create will maintain a perfect square shape automatically.

Method 3: Setting an Exact Pixel Size

If you need a square selection with specific measurements (such as 500 × 500 pixels):

  1. Select the Rectangular Marquee Tool (M).
  2. In the top Options bar, change the Style dropdown menu to Fixed Size.
  3. Enter your desired dimensions in the Width and Height fields (for example, 500 px in both).
  4. Click once on your canvas. A square selection of that exact dimension will instantly appear where you clicked. You can then click and drag inside the selection boundary to reposition it.