How to Change Canvas Size in Photoshop (and Resize the Image)
This guide shows you how to change a Photoshop document’s canvas dimensions and when to use Image Size instead. You’ll learn how canvas changes affect layers, how to anchor the canvas expansion, and how to use simple math inside value fields for quick scaling. You’ll also see how to uniformly resize all layers when needed.
Step-by-step instructions
Open the Canvas Size dialog
Go to Image → Canvas Size…
Review the current Width, Height, and Units.
Set new canvas dimensions
Click Width or Height and type a new value (choose units as needed).
Use equations directly in the field: append +, -, *, or / (e.g., *2 to double, /2 to halve).
Adjust the Anchor to control where the extra canvas is added (arrow diagram shows the effect).
Click OK to apply.
Understand how layers behave
Canvas Size changes the document area only.
All layers retain their original scale and position relative to the canvas.
Resize the entire image and all layers
Go to Image → Image Size…
Enable the link icon to maintain aspect ratio.
Enter a new Width or Height; you can also use equations (e.g., +200, *1.5).
Click OK to scale the whole image and corresponding layers.
