Calculate the minimum riser platform height so Row 2 seats have an unobstructed sightline over Row 1 heads. Based on geometric sightline math used by professional theater designers.
Enter your screen's bottom edge height, the distance from the screen to Row 1, and the spacing between rows. The calculator uses sightline geometry to find the minimum riser platform height for Row 2.
The formula projects a sightline from Row 2's eye position to the bottom of the screen and checks where that line intersects Row 1's head position. The riser height is the minimum elevation needed to push that intersection above Row 1.
Typical home theaters use a riser height of 8–14 inches (20–36 cm). A riser also improves the viewing angle for Row 2 and can accommodate under-riser storage or subwoofers.
Riser height depends on your room layout. With a typical screen bottom at 24 inches, 10-foot first row distance, and 4-foot row spacing, most calculations yield a riser of 8–14 inches. This calculator uses geometric sightline math to give you the exact minimum.
The formula uses similar triangles: the sightline from Row 2 eyes to the screen bottom must pass above Row 1's eye height plus a clearance margin. Riser = required Row 2 eye height − (seat pan height + eye offset above seat).
Typical home theater row spacing is 42–54 inches (3.5–4.5 feet) front-to-back. Luxury stadium seating uses 48–60 inches. Tighter spacing requires a taller riser to maintain sightlines.
A riser only adds a small vertical offset (8–16 inches typically), which has negligible effect on horizontal viewing distance. However, it brings Row 2 viewers closer to the THX/SMPTE ideal viewing angle.