Privacy Screen Distance Calculator

Solving for distance instead of height

Screens usually come in standard panel heights, and fences often have a practical maximum. So the useful question is often not “how tall?” but “where does a screen of this height work?”. Rearranging the sightline equation answers it exactly.

For a viewer with eyes at height E, a target point at distance D with height T, and a screen whose top (minus your safety margin) reaches H, the screen blocks that sightline when:

E + (T − E) × d ÷ D ≤ H

When the viewer looks down on the area (E > T), this becomes a minimum distance from the viewer:

d ≥ D × (E − H) ÷ (E − T)

The calculator applies this to both the near and the far edge of the area and keeps the most demanding result. The far edge usually governs, because its sightline is the flattest. The screen must also stand in front of the area, so the near edge caps the range.

Worked example

A second-floor viewpoint at 4.60 m (15 ft 1 in), a patio from 9 to 13 m away, seated heads at 1.20 m (3 ft 11 in), and a 10 cm safety margin.

Screen height	Works from (distance from viewer)	Up to	Length of the workable zone
1.80 m (5 ft 11 in)	No position works — too low for this viewpoint
2.10 m (6 ft 11 in)	No position works — too low for this viewpoint
2.40 m (7 ft 10 in)	8.80 m (28 ft 11 in)	9.00 m (29 ft 6 in)	0.21 m
2.70 m (8 ft 10 in)	7.65 m (25 ft 2 in)	9.00 m (29 ft 6 in)	1.35 m
3.00 m (9 ft 10 in)	6.50 m (21 ft 4 in)	9.00 m (29 ft 6 in)	2.50 m
3.50 m (11 ft 6 in)	4.59 m (15 ft 1 in)	9.00 m (29 ft 6 in)	4.41 m

A 2.40 m (7 ft 10 in) screen only works in the last 0.21 m before the patio, whereas a 3.00 m (9 ft 10 in) screen gives 2.50 m of freedom. That is typical of views from above: height buys placement flexibility.

When the viewer looks up

If the viewer is lower than what you want hidden — say a neighbor in a lower yard looking up at your raised deck — the relationship flips. The sightline rises toward the deck, so a screen needs to be closer to the viewer to catch it low.

Example: eyes at 1.00 m (3 ft 3 in), deck occupants to hide at 2.50 m (8 ft 2 in) from 6 to 10 m away, and a 1.80 m (5 ft 11 in) barrier. The near edge of the deck governs, and the barrier works up to 3.20 m (10 ft 6 in) from the viewer. Beyond that, the sightline has already risen above it.

Practical checks before you decide

• Width. Near your seating the screen must be wider. Check the width in the planner at the position you pick.
• Access and use. A screen right beside a table can feel enclosing; leave room to move chairs.
• Sun and shade. A tall screen on the sunny side of a patio casts long shadows.
• Local rules. Height limits often depend on distance from a boundary. The calculator does not know them; check local rules before building.

Frequently asked questions

What if no position works for my screen height?

Then the screen is too low to block the whole area from anywhere between the viewer and the area. Options are a taller screen, moving the seating farther from the viewer, lowering what needs to be hidden (for example lounge chairs instead of dining chairs), or adding overhead cover near the seating. The calculator tells you how tall the screen would have to be right at the edge of the area.

Why is the allowed zone so narrow for tall viewpoints?

From a high window the sightlines descend steeply, and a low screen only catches them in the last stretch before they reach your seating. Every additional 30 cm (1 ft) of screen height moves the first workable position noticeably toward the viewer.

Does this calculator check the width too?

No. It answers the height question in profile and assumes the screen is wide enough. Screens placed closer to your area must be wider; use the planner’s top view to see the width needed at the position you choose.

Can I use it for a hedge or a fence?

Yes, for any opaque barrier. For hedges, use the height the hedge is dense enough to block a view, not its nominal height, and remember that growth and seasonal leaf loss change it over time.