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Backyard Review

Free tool

How big a screen, and how far back?

Plug in the throw ratio and brightness from the spec sheet and get screen size, projector distance, seating distance and picture brightness, drawn to scale.

What do you know?

Throw ratio from the spec sheet

:1
:1

Listed as a range like 1.15–1.5:1 when the lens zooms, or a single number (enter it in both boxes) when it does not. Short-throw projectors are about 0.4–0.8.

in
lm

Use the maker's lumens figure. Some brands quote a more flattering kind of lumen.

1.0 for a plain white screen or cloth.

Put the projector

8.4–10.9 ft

from a 100-inch screen

Screen is

87 × 49 in

7.3 × 4.1 ft

Brightness

67 fL

Bright

Sit about

10–14 ft

from the screen

Plenty of headroom, including some tolerance for dusk and stray light.

Your setup, to scale

ScreenSeatingProjector0 ft5 ft10 ft15 ft

The orange band is where the lens can sit for that picture size. Seating ranges come from a 30 to 40 degree view of the screen, a common home-theater guideline.

How this is calculated

Throw ratio = distance ÷ picture width, so width = distance ÷ throw ratio. A lens that zooms gives a range. Diagonal comes from width and the picture shape. Seating distance puts the screen at 30 to 40 degrees of your field of view; sit nearer for more immersion, farther for comfort with a big group.

Brightness in foot-lamberts = lumens × screen gain ÷ screen area in square feet. For reference, cinema standards aim for about 16 fL in a fully dark room. Outdoors, stray light eats into that, and real-world output is often lower than the box figure, especially in color-accurate modes, so more headroom is better.

Lens shift, keystone correction and tilt are not modeled. Check your projector's manual for its real placement range and weather limits.

Keep going

Quick answers

What is a projector throw ratio?

It is the distance from the lens to the screen divided by the width of the picture. A throw ratio of 1.5 means the projector sits 1.5 feet back for every foot of picture width, so a 7-foot-wide picture needs about 10.5 feet. Zoom lenses list a range, such as 1.15 to 1.5.

How far should the projector be from the screen?

Multiply the picture width by the throw ratio. For a 100-inch 16:9 screen, which is about 7.3 feet wide, a 1.2:1 projector sits about 8.7 feet away and a 1.5:1 projector about 11 feet. The calculator does this for any size.

What size projector screen is best for a backyard?

A 100-inch screen is a popular fit for patios and small lawns. Go bigger only if your projector is bright enough for the larger picture, because the same lumens spread across more area make a dimmer image.

How many lumens do I need to watch outside?

More is better, and darkness matters more than any number. As a rough guide, a projector in the low thousands of lumens handles a dark yard on a 100-inch screen, while dim portable projectors want a smaller picture and no ambient light. The brightness readout shows how your numbers compare to a cinema standard.

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