Free planning tool

Projector throw-distance calculator

Answer one simple question: do you know the image width you want, or the place where the projector can sit? We’ll calculate the other measurement.

1. What do you already know?

Use the exact throw-ratio range from the manufacturer’s specification page when you have it.

Put the projector lens within this distance range

9 ft 7 in12 ft 0 in

2.93–3.66 m

Closest lens position
9 ft 7 in
Farthest lens position
12 ft 0 in
Approximate image height
4 ft 6 in
The part people get wrong

Measure from the projector lens to the main projection surface—not from the wall to the back of the projector.

What the calculator is doing

Distance = image width × throw ratio

A 1.2:1 ratio needs about 1.2 units of lens distance for every 1 unit of image width.

Allow extra physical space behind the lens for the projector body, connectors, ventilation, and the stand.

Width8 ft×Throw ratio1.21.5=Lens distance9 ft 7 in12 ft 0 in

This is a planning estimate. Optical zoom, focus limits, lens offset, digital correction, and object depth can change the usable placement. Confirm the result with the manufacturer’s model-specific calculator before buying or mounting.