How to Use the macOS Digital Colour Meter to Find Exact Hex Codes

If you are designing a presentation or building a website, you often need to match a specific colour you saw in an image or on a webpage. Guessing the colour using a standard colour wheel is frustrating and rarely results in an exact match.

Instead of downloading complex third-party design software, you can use a hidden utility built directly into your Mac. The Digital Colour Meter acts like an eyedropper tool for your entire screen, allowing you to sample any pixel and instantly copy its exact mathematical colour value (such as a Hex code or RGB value) to use in your own projects.

How to Open the Digital Colour Meter

Because it is a developer utility, the Digital Colour Meter is hidden inside a subfolder and does not appear on your main Launchpad screen by default.

1. Open a new Finder window.
2. Click on Applications in the left sidebar.
3. Scroll down and open the Utilities folder.
4. Double-click the Digital Colour Meter app to launch it.

Alternatively, you can press Cmd + Space to open Spotlight Search, type “Digital Colour Meter,” and press Enter.

How to Sample a Colour

When the app opens, a small floating window will appear. As you move your mouse cursor around your Mac’s screen, the window acts as a digital magnifying glass.

1. Move your mouse cursor until the crosshair rests exactly over the pixel of colour you want to copy (e.g., the specific shade of blue in a company logo).
2. Look at the Digital Colour Meter window. The left side will display a zoomed-in preview of the pixels under your cursor, while the right side displays the numerical colour values.
3. Once you have found the exact colour, press Cmd + L on your keyboard. This “locks” the aperture, freezing the colour values on the screen so you can safely move your mouse away without losing the reading.

How to Copy Hex Codes and RGB Values

Different design applications require different colour formats. A web developer might need a Hexadecimal (Hex) code, while a video editor might need an RGB (Red, Green, Blue) value.

By default, the Digital Colour Meter displays the RGB values as absolute numbers (e.g., Red: 23, Green: 145, Blue: 255). To change this format and copy the data:

1. Click View in the top menu bar.
2. Hover over Display Values.
3. Select how you want the numbers formatted (e.g., as Hexadecimal or as Decimal).
4. Once the format is correct, click Color in the top menu bar.
5. Select Copy Color as Text (or press Shift + Cmd + C).

You can now paste (Cmd + V) that exact numerical value into Photoshop, Microsoft Word, or your CSS code, guaranteeing a perfect colour match every single time.