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The horizontal distance from the front row's eye position to the focal point being viewed.
The focal point is typically the front edge of the stage floor or the bottom of the screen — the point every row needs an unobstructed sightline to.
The horizontal (not sloped) distance between this row and the next row back.
This is the standard row-to-row seating depth, measured horizontally regardless of the rake angle.
The seated eye height of the patron in the front (reference) row, above the focal point.
A typical seated eye height is around 1.1-1.2m above the floor, adjusted for the vertical distance to the focal point.
The vertical clearance the sightline must clear over the head of the person in front.
A larger C-value gives a clearer, more comfortable sightline over the row in front but requires a taller riser — 60-150mm is a typical range.
Required riser height
0.809 ft
This calculates a single row-to-row riser using the standard C-value method — it does not perform the full recursive multi-row sightline calculation (where each row's riser depends on the cumulative floor profile of all rows in front), which is typically done with specialized theater design software for a complete raked seating section. Verify the assumed eye height and clearance value against your project's specific seating and accessibility requirements.
- Required eye height at next row
- 4.31 ft
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Theater/Auditorium Sightline Riser Height Calculator: 0.809 ft — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
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How this was calculated
Formula source(s)
- Standard theater/auditorium sightline ('C-value') method: for a patron's eye at height H above a focal point (stage floor/screen bottom) at horizontal distance D1, the next row back (at distance D2 = D1 + row spacing) needs eye height H2 = D2×(H+C)/D1 to clear the head of the person in front by a vertical clearance C; required riser height = H2 − H. This is the standard method used in theater/auditorium design references (e.g. Neufert Architects' Data) for a single row-to-row sightline check.
Inputs used
- Horizontal Distance from This Row to the Focal Point (Stage/Screen)
- 33 ft
- Row-to-Row Spacing (Horizontal)
- 3.5 ft
- Seated Eye Height Above Focal Point (Row 1)
- 3.5 ft
- Sightline Clearance Value C (Typically 60-150mm)
- 4.75 in
Intermediate steps
- Required eye height at next row
- 4.31 ft
Confidence note: This calculates a single row-to-row riser using the standard C-value method — it does not perform the full recursive multi-row sightline calculation (where each row's riser depends on the cumulative floor profile of all rows in front), which is typically done with specialized theater design software for a complete raked seating section. Verify the assumed eye height and clearance value against your project's specific seating and accessibility requirements.
What this calculation does not cover
- Assumes every patron looks over the head directly in front. Stagger the seats so each eye looks through the gap between the two heads ahead and the clearance that must be cleared roughly halves — designers commonly work to about 60 mm (2.4 in) on an offset layout against 120 mm (4.7 in) on an aligned one. Enter the aligned value on a staggered plan and the rake comes out hundreds of millimeters taller than the sightline actually needs, taking the aisle steps, the balcony front and the room volume with it.
Computed in your browser — nothing you enter is uploaded. Presented in US customary units and US trade terminology. Where a formula follows a published standard, that standard and its edition are cited beside it on this page; where none governs, the page says so. Local amendments override model codes — verify against the code in force where you build.
Sources checked 2026-09-06 · in the site-wide review of 2026-09-06 · v1.0.1
Regulatory standards & verification citations1
- Standard theater/auditorium sightline ('C-value') method: for a patron's eye at height H above a focal point (stage floor/screen bottom) at horizontal distance D1, the next row back (at distance D2 = D1 + row spacing) needs eye height H2 = D2×(H+C)/D1 to clear the head of the person in front by a vertical clearance C; required riser height = H2 − H. This is the standard method used in theater/auditorium design references (e.g. Neufert Architects' Data) for a single row-to-row sightline check.
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