Free · No login required
Projection Size & Throw Calculator
Calculate screen width, height, diagonal and lens-to-screen distance from image size or available throw distance.
01 / Set your measurements
Length: 0.01–1000 in the selected unit. Changing units keeps the entered number.
Throw ratio: 0.1–10. Use the same minimum and maximum for a fixed lens.
Inputs stay on this page and clear on refresh.
02 / Your result
Projection Size & Throw Calculator
Image width: 4 m Aspect ratio: 16:9 · Throw ratio: 1.2–1.6
- Image width
- 4.000m
- Image height
- 2.250m
- Image diagonal
- 4.589m
- Throw distance
- 4.800–6.400m
Throw ratio = lens-to-screen distance ÷ image width. For aspect ratio a:b, height = width × b/a and diagonal = √(width² + height²). From a diagonal, width = diagonal ÷ √(1 + (b/a)²). Distance range = width × minimum/maximum throw ratio. From a fixed distance, width ranges from distance ÷ maximum ratio to distance ÷ minimum ratio. All lengths use the selected unit. Calculations assume a perpendicular, undistorted image and retain precision until display.
Methodology
How it works
Throw ratio = lens-to-screen distance ÷ image width. For aspect ratio a:b, height = width × b/a and diagonal = √(width² + height²). From a diagonal, width = diagonal ÷ √(1 + (b/a)²). Distance range = width × minimum/maximum throw ratio. From a fixed distance, width ranges from distance ÷ maximum ratio to distance ÷ minimum ratio. All lengths use the selected unit. Calculations assume a perpendicular, undistorted image and retain precision until display.
Method and assumptions documented by Techrider.live
Updated September 15, 2026
Frequently asked questions
How do I use a zoom or fixed lens?
Enter the manufacturer’s minimum and maximum throw ratios for the chosen lens and image format. For a fixed lens, enter the same ratio twice. For example, a 4 m wide 16:9 image is 2.25 m high; a 1.2–1.6 lens needs 4.8–6.4 m of throw.
Does this confirm that my projector will fit?
No. Check the model-specific calculator and installation manual for lens reference points, offset, lens shift, zoom limits and minimum focus distance, especially for ultra-short-throw models. Brightness, ambient light, keystone correction and mounting clearance are not calculated.