Projector Calculator
Plan your home theater layout with accurate screen width, height, viewing distances, brightness in foot-Lamberts, and throw distance. Free projector setup calculator with interactive charts.
About This Calculator
The Projector Calculator helps you design the perfect home theater setup by calculating screen dimensions, optimal viewing distances, screen brightness, and projector throw distance. Whether you are setting up a dedicated home cinema, a conference room projector, or an outdoor movie screen, this tool covers all the essential measurements for a professional installation.
The calculator uses standard geometry formulas to derive screen width and height from the diagonal and aspect ratio: width = diagonal × W / √(W² + H²) and height = diagonal × H / √(W² + H²). Viewing distances follow THX (36° viewing angle for maximum distance) and SMPTE (30° for optimal immersion) standards. Screen brightness is calculated as projector lumens × screen gain ÷ screen area in square feet, with results rated from too dim to ideal for various room lighting conditions. Throw distance is computed by multiplying screen width by the projector's throw ratio range.
Regional Notes
India: Screen sizes are typically listed in inches (diagonal). Common home theater projectors range from 2000-3000 ANSI lumens. Popular screen sizes for Indian homes are 100-120 inches diagonal. Projector prices vary widely with GST at 18% on most models.
United States: Screen dimensions are standardised in inches. THX-certified home theaters are popular among enthusiasts. Projector brightness is universally specified in ANSI lumens. Common throw ratios for UST (ultra-short-throw) projectors are 0.25:1 for living room setups.
United Kingdom: Screen sizes follow the same inch-based standard. VAT is charged at 20% on projector equipment. Ceiling mount installations are common, and throw distance calculations help determine optimal mount positions for 16:9 and 2.4:1 cinema scope screens.
Frequently Asked Questions
How do I calculate the right screen size for my projector?
Enter your screen diagonal in inches and select the aspect ratio (16:9, 16:10, 4:3, etc.). The calculator automatically determines screen width, height, and area using the formula width = diagonal × W / √(W² + H²) for your chosen aspect ratio.
What is the ideal viewing distance for a projector screen?
The ideal viewing distance depends on screen width and resolution. THX recommends a 36° viewing angle for maximum distance, while SMPTE recommends 30° for optimal immersion. This calculator provides minimum, maximum (THX), and ideal (SMPTE) viewing distances in inches.
How bright should my projector be?
Screen brightness is measured in foot-Lamberts (fL). For a completely dark room, 16-22 fL is ideal. Below 12 fL is too dim, and above 22 fL is recommended for rooms with ambient light. Enter your projector's ANSI lumens and screen gain to calculate actual brightness.
What is throw ratio and how do I calculate throw distance?
Throw ratio is the ratio of throw distance (projector to screen) to screen width. Most projectors specify a min and max throw ratio. Multiply your screen width by the throw ratio to get the throw distance in inches, then convert to feet for placement planning.
What screen gain should I choose?
Standard matte white screens have a gain of 1.0. Higher gain screens (1.3-2.8) reflect more light toward the audience, increasing brightness at the cost of narrower viewing angle. For most home theaters, a gain of 1.0-1.3 works well. For ambient light rooms, consider 1.5-2.0 gain.
Can I use this calculator for 4K projectors?
Yes. Select your projector's resolution (720p, 1080p, or 4K) to factor pixel density into viewing distance recommendations. Higher resolutions allow sitting closer to the screen without seeing individual pixels, enabling a more immersive experience.
Is the projector calculator free to use?
Yes, it is completely free to use with no registration required. You can also share your calculation by copying the URL which saves all your input values.
What is the difference between THX and SMPTE viewing distance standards?
THX (36° viewing angle) sets the maximum distance for cinema certification, ensuring the screen fills at least 36° of your field of view. SMPTE (30° viewing angle) is the recommended standard for home theaters, balancing immersion with comfort for long viewing sessions.