Projector Calculator
Find image width, height and lens-to-screen distance from diagonal, aspect ratio and throw ratio.
Formula
Width = diagonal × a/√(a²+b²); height = width × b/a; throw distance = width × throw ratio.
Image diagonal: 100 in · Image width ≈ (100 in × 0.0254 m/in)×(16)÷sqrt((16)^2+(9)^2) · Image height ≈ (2.213801864)×(9)÷(16) · Lens-to-screen distance ≈ (2.213801864)×(1.5)
How to use
- Enter the image diagonal and aspect ratio a:b.
- Enter the projector lens throw ratio from its specifications.
- Read image dimensions and lens-to-screen distance.
Examples
- A 5 m diagonal at 4:3 has 4 m width; throw ratio 1.5 gives 6 m distance.
Frequently asked questions
Is throw ratio based on the diagonal?
No. Throw ratio is lens-to-screen distance divided by image width.
What if my projector has zoom?
Calculate at both ends of its stated throw-ratio range.
Does this choose a projector or seat distance?
No. It excludes brightness, viewing distance, lens offset and keystone; check the model’s installation guide.
Sources
Updated: