Choose Image > Analysis > Ruler Tool, or click the Ruler tool in the toolbox, then use the tool to measure the length of an image area. Choose Image > Analysis > Count Tool, or click the Count tool in the toolbox, then count items in the image.

How do I measure pixels in Photoshop?

Choose Image > Analysis > Set Measurement Scale > Custom. The Ruler tool is automatically selected. Drag the tool to measure a pixel distance in the image or enter a value in the Pixel Length text box. Your current tool setting is restored when you close the Measurement Scale dialog box.

How do I measure in cm in Photoshop?

Select the Right Unit of Measurement

The Photoshop ruler displays pixels by default, but you can change the unit of measurement as desired by right-clicking on the ruler. A drop-down menu will appear with a selection of choices, including inches, points, millimeters, centimeters, pica and percent.