As a general rule you will want to use 1 hinge per every 30 inches of door or fraction thereof.
Hinge heights on internal doors.
All 4 1 2 and 5 butt hinge spacing.
The upper hinge is 7 from top of door to top of hinge the bottom hinge is 9 from the floor.
For a standard internal door its door lock is normally 42 from the floor to the centre of the latch.
Doors over 90 inches but not over 120 inches 4 hinges are recommended.
An 80 inch door is called a 6 8 door pronounced six eight.
Referring to door height.
For a pre hung door measure the width and height of the slab the rough opening space between the studs with no door installed and the thickness of the jamb.
Standard widths for interior doors are 24 28 30 32 and 36 inches while the height must be a minimum of 80 inches.
This is the most common height for passage doors that lead from one room to another.
Opening heights 5 0 through 7 6 one and one half pair butt hinges from under head cl 9 3 4 top of door 9 5 8.
Standard interior door height is 80 inches.
Doors over 60 inches but not over 90 inches need to use 3 hinges.
Doors up to 60 inches need 2 hinges.