There are so many kinds of hinges out there. So many. So many finishes and so many designs. And don't forget about the different sizes (from 3.5" up to 5") and round or square corners. The sizes depend on what type of application you will be installing them to. Bigger sizes are better for bigger and heavier doors and smaller hinges are for the regular doors you will find in most homes that are not solid. Now going back to styles of hinges, you can find pretty much you can imagine. Some can be really decorative with all kinds of designs on the hinge. Some are more plain and simple, and then there is modern, which is so popular now. But what does a modern hinge look like? Modern we all know is a lot of clean lines and can look really simple, but all put together can make a pretty bold statement. Most hinges you will find will have a round knuckle style. The hinge shown below is a modern style with a round knuckle.  width= Linnea if you don't know already has a huge selection of all kinds of modern style hardware and they came out with some great modern style hinges (found here) with square corners and square knuckles, which is not something very common for hinges.  width= The square knuckle style makes the hinge stand out more because it's different and different means it is more unique and that makes things interesting. Modern can be so simple and also so sleek. This square knuckle style hinge is available in 3.5", 4", and 4.5". So depending on what type of door you are installing these will depend on the size you choose. The bigger and heavier the door, the bigger hinge you will need. Any of the square knuckle hinges are available in brushed nickel, polished chrome or oil rubbed bronze finishes.  width=