How to Change Units in Photoshop (Pixels, Inches, and Millimeters)

By Kelly Barkhurst

July 8, 2025

7 Min read

In Print Graphic Design

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If you are new to Photoshop, understanding how measurements work can be confusing, especially when switching between web and print projects. Photoshop lets you view and enter sizes in pixels, inches, millimeters, and more, but not all unit fields or dropdowns change automatically. This guide will help you learn how to change units in different parts of Photoshop. It also includes a handy trick to change the top toolbar units using Control-click on Mac or right-click on Windows.

🎥 Prefer to watch? Check out the full video tutorial on YouTube.

1. Change Your Global Unit Settings

Start by setting your preferred units in Photoshop’s settings.

Open a document and go to:

On a Mac, Photoshop then Settings and then Units and Rulers
On Windows, Edit then Preferences and then Units and Rulers

Here, you can choose pixels, inches, or millimeters for your rulers. Click OK to apply your choice. This setting controls your rulers and how dimensions appear in panels such as Properties.

2. Drawing Shapes and Mixed Units

Draw a shape using the Rectangle Tool (shortcut U).

When your shape is selected, open the Properties panel. If it is not visible, open it from Window then Properties.

You will see the width and height displayed in the units you chose. However, you may notice that the top toolbar still shows different units. This happens because the top toolbar units do not always update automatically….

You can have one unit of measurement shown on the option toolbar and another in the Properties Window. — This image shows an example of the top toolbar showing the shape size in pixels and the properties window showing the same shape in inches.

3. The Toolbar Trick

To change the units in the top toolbar or the Properties window:

On a Mac, Control-click on the units label (for example, “px” or “in”).
On Windows, right-click on the units label.

A menu will appear where you can switch to pixels, inches, millimeters, or other units. This will allow you to make the toolbar match your Properties panel.

Right Click or Control Click (Mac) the units measurement to change in Photoshop.

This trick is especially useful because just clicking normally on the unit measurement label does nothing.

4. Do the Unit Settings Stick?

Changing the Units and Rulers preference stays saved between Photoshop sessions.

When I make a change in the Options Toolbar and then create a new document that unit change remains. Also, that unit change will remain as I tab through open files in PhotoShop; however, if I restart Photoshop, that manual change will no longer be visible.

5. Entering Measurements Manually

You can also type measurements with units included directly into unit fields, even when creating shapes.

For example, type 50px for pixels, 3in for inches, or 75mm for millimeters. Photoshop will understand and adjust sizing accordingly.

You can change the units shown in dialog boxes the same way as you do in the toolbar or Properties window: Control-click on Mac or right-click on Windows the unit label.

Watch Video Demonstration

Hi, so today we’re going to work on units of measurement in Photoshop. So, if you have a document open, you can come to your Photoshop and this is on a Mac, Settings> Units & Rulers and you can look over here on the left side for Units & Rulers and you can set it to pixels, inches and other measurements, but pixels and inches are probably what you use the most. So we’re going to go ahead and set this to inches. Alright, now we’re going to navigate to a rectangle, so a vector shape in PhotoShop and if I draw it (it is drawn) and I want to draw your attention to two places. One is the Properties window that’s over here on the right. If you do not have your Properties window, and I’ll see how visible you can go to Window > Properties. Okay, Window > Properties. And because I have the box selected, you can see that by the blue nodes around the corners. And I have the units of measurement set to inches for my rulers. This property box is showing me my width and my height in inches. Now, interesting, the dialog box up here at the top is showing pixels. So that can be kind of frustrating because a lot of times we get used to working from this top box. So a trick to be able to change it to the units of measurement you want. On your Mac, you’re going to select the where that pixels is and you’re going to click control click and that’s going to bring up a dialogue. So if you’re just trying to click around you’re not going to get a drop down dialogue. But if you control-click on your Mac and then click where the PX is shown or the IN you can now switch that to inches and you can see now it’s showing me 3.91 inches the same as in my Properties box. Same trick. Click control-click on your Mac, and you can switch between units so your rulers are not changing here but you are able to control click and change what you’re seeing in measurement. Now what I have found is that these boxes if I have changed this to inch and this is still on pixel, if I open and create a new file and I draw a box, you can see that this is staying the same so it doesn’t seem to be saved with the file it seems to be saved with your Photoshop preferences. So you can see that I still have units of measurement or inches here, but this box is showing me inch and this one is still showing me pixels. alright the other thing to think about is if I click once with my box. And you can see it is actually changed even here in my dialog box at the first one is inches the second one is pixels. Now even in this dialog box, I can control-click and get it to inches too so let’s say the these are inches but I could actually type in and say 50px 50px and when I click ok it’s made it very small 50 pixels. So within any of these dialog boxes I can see here it’s 0.35 inches or 50 pixels and if I would control click switch back to pixels I can see it’s 50.4 pixels here. But in general those are some of the tips for how you can change units of measurement within these dialog boxes of create rectangle properties and also your shape bar up at the top. Alright, I hope that helps.

Final Thoughts

Whether you are working on a website or preparing files for print, knowing how to control units in Photoshop helps keep your designs accurate. While many users know how to set units in Preferences, the Control-click or right-click trick for changing units is often overlooked and is very helpful.

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About the author

Kelly Barkhurst

Designer to Fullstack is my place to geek out and share tech solutions from my day-to-day as a graphic designer, programmer, and business owner (portfolio). I also write on Arts and Bricks, a parenting blog and decal shop that embraces my family’s love of Art and LEGO bricks!

By Kelly Barkhurst July 10, 2025