Most doors have three most hinges today are sold in pairs.
How many hinges on an internal door.
Fire door hinges are manufactured very well so they can do what they need to do in case of an emergency.
A pair of hinges is two complete sets of hinges as displayed below.
Doors up to 60 inches need 2 hinges.
Usually at least 3 hinges need to be fitted on a door.
Doors over 90 inches but not over 120 inches 4 hinges are recommended.
If you have a particularly heavy door and want to use four hinges divide the top to bottom measurement by three instead of two and place your hinges accordingly.
Maybe the 3 hinged doors you see are not hollow core.
As a general rule you will want to use 1 hinge per every 30 inches of door or fraction thereof.
Regular hollow core doors need only 2 hinges.
Generally for normal internal doors you should only need between a 1 and 4 hinge class.
Light weight internal domestic doors may be fitted with only 2 hinges.
The chart below will provide you with the number of hinges that are needed based on the height of your door.
For doors over 2200mm tall then four hinges can be used to prevent warping.
Doors with a security function need to have at least 3 hinges as this makes them more difficult to force.
A couple things to make a note of before purchasing your door hinges.
Referring to door height.
Opening heights 7 6 1 16 through 10 0 two pair butt hinges from under head cl 9 3 4 top of door 9 5 8.
References stanley hardware.
Size of door doesn t matter besides it would.
Doors over 60 inches but not over 90 inches need to use 3 hinges.
Standard internal doors i advise 3 x 3 roller bearing hinges per door top hinge set 6 from the top of the door bottom hinge set 9 from the bottom of the door and finally the middle hinge set halfway between the top and bottom hinge.
Standard 60 doors typically require three hinges but anything taller than that may require more.
To roughly between 5 to 8.
However this changes when you come to doors like fire doors the hinge class that is needed will increase.