If you're looking for a router to use for your door, you'll need to consider the size of the door and the type of material it's made from. For a standard sized door, a router with a 1/2 bit will suffice. However, if your door is made from thicker material or is larger than average, you may need to use a router with a 3/4 bit. Be sure to consult the manufacturer's guidelines to ensure that you choose the right size router bit for your project.