Projection Throw Distance Calculator
Quick answer: Enter throw ratio and screen width. Get throw distance, screen height/diagonal, and recommended ANSI lumens.
Calculate projector throw distance, screen dimensions, and recommended brightness in ANSI lumens for any lens throw ratio and screen size. Works for any projector — Christie, Barco, Epson, NEC, Panasonic — using the universal throw distance formula.
Advertisement
Last reviewed: April 2026Report an error
e.g. 1.5 for a 1.5:1 lens. Ultra-short: 0.3-0.5. Long throw: 3.0+.
Throw Distance
6 m
Projector should be 6 m from the screen. Screen height: 2.25 m. Diagonal: 4.59 m (181″). Recommended brightness: 4,838 ANSI lumens for moderate ambient.
Throw Distance
6 m
Screen Height
2.25 m
Diagonal
181″
Recommended Lumens
4,838
Formula: throw distance = throw ratio × screen width. Lumens for moderate ambient (50 lumens/ft²).
Advertisement
The Formula
throw_distance = throw_ratio × screen_width
- throw_ratio = Lens specification (e.g. 1.5 for a 1.5:1 lens)
- screen_width = Width of the projected image
- screen_height = screen_width ÷ aspect_ratio
- lumens = ≈ 50 ANSI lumens per ft² for moderate ambient light
How to Use This Projection Throw Calculator
- 1Enter the projector lens throw ratio (e.g. 1.5 for a 1.5:1 lens).
- 2Enter your screen width in meters or feet.
- 3Pick aspect ratio (16:9 standard, 1.85 cinema, 2.35 cinemascope).
- 4Read throw distance, screen height, diagonal, and recommended brightness.
Frequently Asked Questions
- A lens spec: throw ratio = throw distance ÷ screen width. A 1.5:1 lens means the projector sits 1.5× the screen width away. Lower ratio (0.5:1, "ultra short throw") = closer; higher (3:1+, "long throw") = farther.
- Zoom lenses have a range, e.g. 1.2-1.8:1. Use the minimum end if your projector must be close, the maximum if farther away. The calculator can be run twice for the two ends of the range.
- For a low-ambient room (cinema, dark): 25 ANSI lumens per ft² of screen. Moderate ambient (corporate ballroom): 50 lumens/ft². High ambient (lobby with windows): 100+ lumens/ft². Calculator uses 50/ft² as a moderate default.
- No — keystone is digital (warps the image to compensate for off-axis projection). It does NOT change the geometric throw distance, but it does reduce native resolution. Avoid heavy keystone if possible — use lens shift or physical alignment instead.
- Same throw math, but you need a projector capable of "rear" projection (image flipped horizontally) and a translucent screen. Throw ratio is calculated the same way, just measured from the back.
Advertisement
Related Calculators
</> Embed this calculator on your website
<iframe src="https://calqpro.com/calculators/projection-throw-distance-calculator" width="100%" height="600" frameborder="0" title="CalQpro Calculator" loading="lazy"></iframe> <p>Powered by <a href="https://calqpro.com">CalQpro</a></p>
Advertisement