Estimating Throw Distance Formula

The formula for estimating throw distance is:

Distance = Screen Width * Throw Ratio

Where:

Distance is the distance from the front of the lens to the closest point on the screen
Screen Width is the width of the projected image
Throw Ratio is the ratio of throw distance to image width

Refer to the owner's manual of your projector and lens combination to find an accurate formula for your specific projector.

Throw Distance Example

A projector has an installed lens with a throw ratio of 2.0:1. The width of the screen in the room is 72 inches (1829 mm).

Step one:

Estimate the distance from the projector lens to the screen.

Step two:

Distance = Screen Width * Throw Ratio

Distance = 72 inches * 2.0

Distance = 144 inches (3658 mm)

Throw Distance Example

A projector has an installed lens with a throw ratio of 2.5:1. The width of the screen in the room is 72 inches (1829 mm).

Step one:

Estimate the distance from the projector lens to the screen.

Step two:

Distance = Screen Width * Throw Ratio

Distance = 72 inches * 2.5

Distance = 180 inches (4572 mm)

Compare the two calculations. Notice that the screen width stays the same, but the throw ratio determines how far away the projector is from the screen.

Throw Distance Example (metric only)

Here is an example of a metric-only throw distance calculation:

A projector has an installed lens with a throw ratio of 2.0:1. The width of the screen in the room is 3050 mm.

Step one:

Estimate the distance from the projector lens to the screen.

Step two:

Distance = Screen Width * Throw Ratio

Distance = 3050 * 2.0

Distance = 6100 mm