Butt hinges (standard) vary in size from 1 inch (25mm) up to about 8 inches (200mm). However the most common sizes are 2 ½ inch (64mm), 3 inch (75mm) and 4 inch (100mm). A hinge is measured or described by its height, which usually refers to the length of the joint knuckle. If this is followed by another size, this will refer to the width of the hinge when laid open.
Sizing of Butt Hinges
64mm hinges are used for cabinet doors and thin standard doors. The most common application being on bespoke kitchen doors and wardrobe doors.
75mm butt hinges are most commonly used on standard internal doors (35mm thick doors) and a pair is usually sufficient. However, for aesthetic reasons many people will put three hinges on each door.
100mm hinges are most commonly found on external doors and internal fire doors (45mm thick doors). Fire doors by regulation must have three hinges per door.
Most brass hinges for household/commercial door applications contain washers at the pivot which will be made of steel, stainless steel or phosphor bronze, depending on the application of the hinge. These washers prolong the life of the hinge and give it a greater load carrying capacity.