The calculation for throw distance is a direct function of the desired image size and the projector's

lens characteristics. The standard formula is: Throw Distance = Throw Ratio × Image Width. In an

existing installation, the screen is already in place, making its size (specifically its width) the

primary, known variable required to begin the calculation. Therefore, evaluating the screen size is

the foundational first step before any other factors can be considered or calculated.

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1. AVIXA. (2020). CTS Certified Technology Specialist Exam Guide, Third Edition. McGraw-Hill.

In Chapter 5, "Creating AV Solutions," the section on "Calculating Throw Distance" explicitly

states, "Throw distance is the distance from the projector’s lens to the screen. It is calculated by

multiplying the throw ratio by the screen width." This establishes screen width (derived from

screen size) as the primary variable.

2. ANSI/INFOCOMM 3M-2011. Projected Image System Contrast Ratio. This standard,

foundational to AVIXA principles, bases all system performance calculations on the

characteristics of the projected image, whose size is determined by the screen. The geometric

relationship between projector and screen size is the basis for all placement calculations.

3. He, G., & Feng, W. (2005). Projection Displays. In Wiley-SID Series in Display Technology.

John Wiley & Sons. Chapter 4, "Projection Optics," details the optical formulas governing

projection systems, where image size (determined by the screen) is a fundamental variable for

calculating the required projection distance (throw distance). (Available via IEEE Xplore/Wiley

Online Library for academic access).