BenQ Projector Calculator: Find Throw Distance

A BenQ projector calculator estimates the image size or projector-to-screen distance for a particular model, using its throw ratio. Enter the screen dimensions and the model’s throw ratio to calculate the distance; the result is a planning estimate, not a substitute for checking that projector’s specifications.

Formula

For a standard projector lens, throw ratio is the distance from the lens to the screen divided by the projected image’s width:

Throw ratio = throw distance ÷ image width

Rearranged for the calculator:

Throw distance = image width × throw ratio

• Image width (w) is the width of the projected picture, in metres.
• Throw ratio (r) is a dimensionless value specified for the projector lens.
• Throw distance (d) is the approximate distance from the lens to the screen, in metres. The second output converts that distance to feet.

The formula applies to the width of the projected image, not its diagonal measurement. A projector’s zoom range may provide a minimum and maximum throw ratio; calculate both ends to get an approximate placement range.

Worked Example

Using the calculator’s default values—image width 2.21 m and throw ratio 1.5:

1. Multiply the image width by the throw ratio: 2.21 m × 1.5 = 3.315 m.
2. Round the distance to two decimal places: 3.32 m.
3. Convert to feet: 3.315 × 3.28084 = 10.875… ft, which rounds to 10.88 ft.

These are approximate lens-to-screen distances. Room layout, lens position and installation tolerances may affect the final placement.

What a BenQ Projector Calculator Does

“BenQ projector calculator” usually refers to a model-specific projection calculator or a general throw-distance calculator used with the specifications for a BenQ projector. The calculation helps answer practical questions such as whether a projector can fill an existing screen from a planned ceiling mount, or how large an image may be possible from a given location.

There is no single throw ratio that applies to every projector from a manufacturer. The correct ratio depends on the exact model and, where relevant, the installed lens. Look up the model’s published throw-ratio range rather than choosing a value based only on the brand. A manufacturer’s calculator may also account for model-specific lens shift, zoom, projection orientation or other installation details.

How to Use the Calculator

1. Find the exact projector model. Check its product specifications or manual for the throw ratio. If there is a range, keep both endpoints.
2. Measure the screen’s visible image width. Use the picture area, not the diagonal, frame or wall width. Enter the width in metres for this calculator.
3. Calculate the distance. Multiply the image width by the throw ratio. For a zoom range, calculate once using the low ratio and again using the high ratio.
4. Compare the result with the room. Measure from the intended lens position to the screen surface and allow for mounting and adjustment.
5. Verify with model-specific documentation. Confirm the installation against the projector’s manual or its dedicated calculator before drilling or fixing a mount.

For example, a 2.21 m-wide image and a 1.5 throw ratio give a lens-to-screen distance of about 3.32 m. This example illustrates the formula; it does not describe every BenQ model.

Screen Size, Aspect Ratio and Units

Screen size is often advertised by diagonal, but throw calculations generally use image width. For a 16:9 image, width is approximately 0.872 times the diagonal. Thus, a 100-inch diagonal image is about 87.2 inches wide, or 2.21 m. Applying a 1.5 throw ratio gives an approximate distance of 3.32 m (10.88 ft).

That shortcut only applies to a 16:9 image. For another aspect ratio, calculate width from the diagonal and the aspect ratio, or measure the intended picture width directly. If using inches and feet, keep the units consistent: image width in inches multiplied by throw ratio gives distance in inches; divide by 12 for feet. The calculator above accepts metres and also displays feet.

Do not enter a diagonal where the calculator asks for width. Doing so overstates the required distance. Also check that the screen’s advertised diagonal describes the visible image rather than the outer frame.

Placement Limits and Common Mistakes

The throw-ratio calculation is geometric. It does not guarantee that a projector will fit a room or produce the desired brightness and picture quality. Its distance is measured from the lens to the screen, not from the back of the projector, the ceiling mount’s centre, or the wall behind the projector. The lens may be set back from the chassis, so use the manual’s drawings when measuring a physical installation.

• Using the wrong ratio: Verify the model and lens. A ratio from another projector can produce a substantially incorrect estimate.
• Confusing zoom endpoints: Calculate the range using the model’s specified minimum and maximum ratios. Check how its documentation defines those endpoints.
• Assuming lens shift changes throw ratio: Lens shift adjusts the position of the image within supported limits; it does not replace the throw-distance calculation.
• Ignoring image geometry: Digital keystone correction may alter or reduce the usable image. Plan for a level, square installation where possible, following the manual.
• Treating rounded values as exact: The displayed result is rounded to two decimal places. Use unrounded figures for intermediate calculations and follow the manufacturer’s placement guidance.

Throw ratio alone does not determine whether the projector’s resolution, brightness, connectivity, or image quality suits a room. Those require separate checks. The simple formula also cannot account for every optical design or installation adjustment; the model’s documentation takes precedence.

Frequently Asked Questions

How do I calculate BenQ projector throw distance?
Multiply the projected image width by the exact model’s throw ratio. For example, 2.21 m × 1.5 gives 3.315 m, or about 3.32 m.

Should I use screen diagonal or width?
Use the visible image width. If you only know the diagonal, convert it using the image’s aspect ratio first; a 16:9 screen’s width is about 0.872 times its diagonal.

Where can I find my projector’s throw ratio?
Look in the specifications or manual for the exact model and lens. If the projector has a zoom lens, the documentation may list a range instead of one ratio.

Is throw distance measured from the projector’s back?
No. The formula refers to the lens-to-screen distance. The lens position may differ from the projector’s rear edge or mount point, so consult the model’s installation drawing.

Can I use the same calculator for another projector brand?
Yes. The basic geometric formula works with any projector that provides a compatible throw ratio, but use that specific model’s figures and installation documentation.

Related

• Bytes Calculator
• Audio File Size Formula: Calculate Uncompressed Audio
• Audio File Size Calculator for Windows 10

in w | Image width | m | 2.21 | 0
in r | Throw ratio | - | 1.5 | 0
out d | Throw distance | m | w * r | 2
out f | Throw distance | ft | w * r * 3.28084 | 2