A door that sags or no longer fits the opening squarely often only needs to have minor adjustments to the hinge. Most home interior and exterior doors use loose pin butt hinges. Butt hinges are two piece hinges that join with a hinge pin. Raising the butt hinge on the jamb resolves most sagging door issues. Raising the butt hinge requires removing the door from the opening temporarily.
Slide a flathead screwdriver between the hinge pin head and the hinge sleeves. Pry the pin up enough that you can grab the pin with a pair of pliers.
Grasp the top of the pin with a pair of pliers and pull it straight out of the hinge sleeves. Repeat this process for each hinge on the door. Open the door and pull it away from the jamb.
Remove the screws securing the top butt hinge leaf to the door jamb with a Phillips-head screwdriver. Remove the leaf and place the leaf on a piece of cardboard. Trace the outline of the leaf onto the cardboard with a pencil.
Cut the butt hinge leaf tracing out of the cardboard with a utility knife. Place the butt hinge leaf back onto the door jamb, with the cardboard between the leaf and the jamb. Secure the leaf to the jamb with the retaining screws.
Line up the sleeves of the door hinge leaves with the jamb leaves. Insert the pins through the sleeves from the top. Tap the pins down with a hammer until the hinge pins are seated on the top sleeve.