About rulers

Rulers help you position images or elements precisely. When visible, rulers appear along the top and left side of the active window. Markers in the ruler display the pointer’s position when you move it. Changing the ruler origin (the (0, 0) mark on the top and left rulers) lets you measure from a specific point on the image. The ruler origin also determines the grid’s point of origin.

To show or hide rulers, choose View > Rulers.

Change a ruler’s zero origin

  1. (Optional) Choose View > Snap To, then choose any combination of options from the submenu. This snaps the ruler origin to guides, slices, or document bounds. You can also snap to the grid.
  2. Position the pointer over the intersection of the rulers in the upper-left corner of the window, and drag diagonally down onto the image. A set of cross hairs appears, marking the new origin on the rulers.

    You can hold down Shift as you drag to make the ruler origin snap to the ruler ticks.

    To reset a ruler’s origin to its default value, double-click the upper-left corner of the ruler.

    Photoshop Dragging rulers
    Dragging to create new ruler origin

Change the unit of measurement

  1. Do one of the following:
    • Double-click a ruler.

    • (Windows) Choose Edit > Preferences > Units & Rulers, or right-click the ruler and then choose a new unit from the context menu.

    • (Mac OS) Choose Photoshop > Preferences > Units & Rulers, or Control-click the ruler and then choose a new unit from the context menu.

  2. For Rulers, choose a unit of measurement.

    Changing the units on the Info panel automatically changes the units on the rulers.

  3. For Point/Pica Size, choose from the following options:

    PostScript (72 points per inch)

    Sets a unit size compatible for printing to a PostScript device.


    Uses 72.27 points per inch, as traditionally used in printing.

  4. Click OK.
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