16 Mm
All 16 mm perforations are rectangles with rounded corners and are 0.0500" high by 0.078" wide. The tolerance for these perforation dimensions was reduced to 0.01 mm in 1989, which allowed 16 mm camera manufacturers to slightly enlarge their registration pins and thus improve image registration and steadiness tolerances to less than 1/750th of the image height of the 16 mm frame.
Read more about this topic: Film Perforations