Projector Screen Size Calculator
Find screen dimensions from throw distance and throw ratio, or verify your room layout.
This tool is for informational and educational purposes only. It is not a substitute for professional financial, medical, legal, or engineering advice. See Terms of Service.
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Request a ToolHow to Use the Projector Screen Size Calculator
- Select a preset to load the throw ratio for common projector types: short throw, ultra-short throw, and standard projectors.
- Enter the throw distance in feet. This is the distance from the projector lens to the screen surface. Measure from the wall or ceiling mount position where you plan to install the projector.
- Set the throw ratio. The throw ratio is the distance divided by the screen width. A 1.5:1 throw ratio projector at 12 feet produces an 8-foot wide image. Check your projector's specification sheet for the exact ratio or range.
- Set your aspect ratio. Most modern projectors use 16:9 for standard HD and 4K content. Use 4:3 for older content or native SVGA projectors.
- Read the result. The calculator shows the projected screen width, height, and diagonal in feet and inches.
About Projector Throw Ratios
Throw ratio determines how much distance a projector needs to create a given image size. A throw ratio of 1.5 means the projector must be 1.5 feet away for every foot of screen width. Short-throw projectors (0.4-1.0:1) can sit close to the screen, making them ideal for small rooms or above a whiteboard. Ultra-short-throw projectors (0.1-0.4:1) can sit just inches from the screen and are common in living room setups where ceiling mounting is not practical.
Standard home projectors typically have throw ratios between 1.3:1 and 2.0:1. At 15 feet with a 1.6:1 throw ratio, you get a 9.4-foot (113-inch diagonal) image — a legitimate home theater size. Many projectors include a zoom lens with a range of throw ratios (e.g. 1.3-2.1:1), giving flexibility in placement.
Frequently Asked Questions
How far should a projector be from the screen for 100 inches?
A 100-inch 16:9 screen is about 87 inches (7.3 feet) wide. With a standard 1.5:1 throw ratio projector, you would need the projector about 10.9 feet from the screen. At 1.3:1, it is about 9.4 feet. Check your projector's specific throw ratio; many zoom lenses allow a range of distances to fine-tune the image size.
What throw ratio do I need for a small room?
For rooms under 12 feet deep, look for a short-throw projector with a throw ratio under 1.0:1. For rooms 8-10 feet deep, ultra-short-throw projectors at 0.2-0.4:1 can produce 80-100 inch images from just 2-3 feet away. These also reduce shadow interference when people walk in front of the screen.
Does throw distance affect image quality?
Throw distance itself does not affect image quality within the projector's zoom range. What matters more is using the projector at its native aspect ratio, ensuring the lens is aligned with the screen (or using lens shift and keystone correction carefully), and that the room is adequately dark. Projector brightness (lumens) becomes more important as the image gets larger.
What screen size is good for a home theater?
The Society of Motion Picture and Television Engineers (SMPTE) recommends a minimum viewing angle of 30 degrees. For a typical 12-foot viewing distance, that translates to about a 100-inch (8.3-foot) screen. Most dedicated home theaters use screens between 100 and 135 inches. Larger screens require more projector brightness (at least 2,000-3,000 lumens for a dark room).