PMeter is a very handy pixel meter. There are plenty of desktop rulers around, but it’s hard to find a good one, which is free. PMeter is a simple to use desktop ruler allowing to switch between 3 user configurations easily. For each configuration you can set width and colors individually, choose to add a desktop magnifier to your ruler, and more.
I onestly use it more for the color picker, very useful tool for a web designer if he wants to know exactly the color of anything from the web to your desktop.
After you select your area or point where you want to see the color code, just release the mouse click and click on “Color” button. It will open a new window with the color codes that you where searching for :)