The regular iPhone 16 is about 5.81 inches (147.6 mm) long (tall).

That’s the top‑to‑bottom height of the phone, not the screen size (the screen itself is 6.1 inches measured diagonally). The width is about 2.82 inches (71.6 mm) and the thickness is about 0.31 inches (7.8 mm), but if you just care “how long,” it’s 5.81 inches.