BenQ Projector Throw Calculator

Enter Projector Details

Screen diagonal

Screen unit

Aspect ratio

Custom aspect width

Custom aspect height

Quick ratio preset

Minimum throw ratio

Maximum throw ratio

Distance unit

Room depth

Projector body depth

Rear cable clearance

Fixed lens distance

Lens offset percent

Mount style

Example Data Table

Setup Type	Diagonal	Aspect	Throw Ratio	Approximate Distance
BenQ standard zoom sample	100 in	16:9	1.15 to 1.50	8.35 ft to 10.89 ft
BenQ short throw sample	100 in	16:9	0.69 to 0.83	5.01 ft to 6.03 ft
BenQ long throw sample	120 in	16:9	1.80 to 2.20	15.69 ft to 19.17 ft

Formula Used

Screen width = diagonal × aspect width ÷ √(aspect width² + aspect height²)

Screen height = diagonal × aspect height ÷ √(aspect width² + aspect height²)

Throw distance = screen width × throw ratio

Screen width from fixed distance = lens distance ÷ throw ratio

Lens offset distance = screen height × offset percent ÷ 100

How to Use This Calculator

Enter your preferred screen diagonal and unit.
Select the aspect ratio used by your screen or content.
Add the minimum and maximum throw ratios from the projector manual.
Enter room depth, projector body depth, and rear cable clearance.
Use fixed lens distance when a mount location already exists.
Press calculate and review the result above the form.
Export the result as a CSV file or a simple PDF report.

BenQ Throw Planning Guide

A projector throw plan starts with image width. The diagonal is useful, but distance is based on width. This calculator converts diagonal size into width and height. It then applies the selected throw ratio. The result shows the closest and farthest lens positions.

Why Throw Ratio Matters

Throw ratio describes the relationship between lens distance and image width. A ratio of 1.50 means the lens sits 1.50 units away for each unit of image width. Many BenQ models use a zoom lens. That is why a minimum and maximum ratio are both entered. The lower ratio creates a larger image from the same position. The higher ratio creates a smaller image from the same position.

Room Fit Checks

A projector may fit on paper but fail in a real room. Ceiling mounts, rear shelves, and cable space reduce usable depth. This tool subtracts projector body depth and rear clearance from room depth. It then compares the remaining lens distance with the required throw range. This gives a practical placement note before drilling holes.

Screen Size From Distance

Sometimes the room distance is already fixed. In that case, enter the available lens distance. The calculator estimates the screen diagonal range at that point. This helps when replacing an older projector or using an existing ceiling mount. It also helps compare models before buying.

Lens Offset Notes

Lens offset estimates the vertical difference between the screen edge and lens center. A positive offset often means the image rises above the lens on a table setup. Ceiling mounting may invert that relationship. Always confirm the exact manual for your model before final mounting. Lens shift, keystone, and digital correction can change the final adjustment method.

Best Use Practice

Measure from the lens, not from the back case. Use the same units for room values. Add extra clearance for cables, ventilation, and service access. Test the image before making permanent holes. Select a screen size that leaves zoom adjustment available. Avoid using the extreme end of zoom when possible. A small margin makes focus, alignment, and future changes easier. Record each test value so installers can repeat the setup quickly and avoid confusion during final alignment later onsite.

FAQs

What is projector throw distance?

Throw distance is the space between the projector lens and screen. It is calculated from image width and the throw ratio.

Where do I find a BenQ throw ratio?

Check the product manual, specification sheet, or official model page. Use the exact ratio range for the model you plan to install.

Does diagonal size decide throw distance?

Not directly. The calculator first converts diagonal size into screen width. Throw distance is then calculated from that width.

Why are minimum and maximum ratios needed?

Zoom lenses have a range. The minimum ratio gives the closest placement. The maximum ratio gives the farthest placement.

Should I measure from the lens or projector back?

Measure from the lens. Throw ratio is based on lens position, not the back, feet, or mount plate of the projector.

What does room fit check mean?

It compares usable lens distance with the needed throw range. It also subtracts projector depth and rear cable clearance.

Can this calculator handle ceiling mounts?

Yes. Select ceiling mount for a clearer lens offset note. Still confirm the final offset with the model manual.

Is the PDF report detailed?

The PDF export gives a quick result summary. Use it for notes, early planning, installer review, or client approval.