Half of 7/8 inches is 7/16 inches (0.4375″, 11.11 mm).
How to Calculate It
Convert 7/8 to an improper fraction, divide by 2, then simplify. 7/8 = 7/8, divided by 2 = 7/16, simplified to 7/16.
On the Tape Measure
The mark at 7/16 inches (0.4375″) is a standard mark on all tapes.
Where 7/8″ Comes From
7/8″ is a standard dimension in finish carpentry. Door stops are commonly 7/8″ thick, many trim profiles use a 7/8″ reveal, and standard hinge placement references 7/8″ as a setback. Stair nosing and window stool profiles also use this dimension.
When You Need Half of 7/8″
7/16″ is the cabinet-making standard for inset door hinge setback. It is also the depth of a standard rabbet cut for cabinet backs, the offset for centered reveal lines on face frames, and the strike plate mortise setback from the door face on many pre-hung doors.
Finding 7/16″ on the Tape
Locate 1/2″ and count back one small tick. That single tick is 7/16″ — the seventh mark from zero on a tape showing 16ths, sitting exactly between 3/8″ and 1/2″.