Projector Screen Size Calculator
Last updated: June 2026
Formula
Throw ratio = distance / screen width. Screen width = distance / throw ratio. For 16:9 screens, diagonal = screen width / 0.872.
| Screen | Standard | Short | Ultra short |
|---|---|---|---|
| 80in | 1.7m | 0.55m | 0.27m |
| 100in | 2.2m | 0.55m | 0.35m |
| 120in | 2.6m | 0.66m | 0.42m |
| 150in | 3.3m | 0.83m | 0.52m |
About this calculator
The Projector Screen Size Calculator estimates screen diagonal, screen width, screen height, or throw distance using projector throw ratio. It helps plan home cinema rooms, office presentations, gaming setups, and short-throw projector placement.
Projector throw formula
Throw ratio compares projector distance with image width. A lower throw ratio creates a larger image from a shorter distance.
- throw ratio = distance / screen width
- screen width = distance / throw ratio
- 16:9 diagonal = screen width / 0.872
How to use the projector screen size calculator
- Choose whether you know room distance or desired screen size.
- Select standard, short throw, ultra short throw, or custom throw ratio.
- Enter available distance or desired screen diagonal.
- Review screen size, width, height, or throw distance.
- Compare the result with your projector manual before buying a screen.
Worked examples
Standard projector from 3m
Input: 3m distance, throw ratio 2.0
Calculation: Screen width = 3 / 2 = 1.5m. Diagonal = 1.5 / 0.872.
Result: About 68 inches diagonal.
100 inch short throw
Input: 100 inch screen, throw ratio 0.5
Calculation: Screen width about 2.21m. Distance = 2.21 x 0.5.
Result: About 1.1m throw distance.
Throw ratio explained
A standard projector may need a long distance to create a large image. A short-throw projector can create a large image from closer to the screen. Ultra short throw models sit very close but often need careful alignment and a suitable screen.
Room planning notes
Projector placement is affected by lens shift, zoom range, ceiling mounts, seating position, screen gain, ambient light, and speaker placement. Use the calculator for the first estimate, then check the model-specific throw calculator or manual.
Projector planning disclaimer
This calculator assumes a 16:9 screen and simple throw-ratio geometry. Real projectors may have zoom ranges, offsets, lens shift limits, keystone limits, and mounting constraints.
Frequently asked questions
What is throw ratio?
Throw ratio is projector distance divided by image width. A 2.0 throw ratio means the projector sits twice as far away as the image is wide.
Is short throw better?
It depends on the room. Short throw can work in smaller rooms, but alignment and screen flatness become more important.
Does screen size equal screen width?
No. Screen size is the diagonal measurement, just like a TV.
Can I use this for 4:3 screens?
This calculator assumes 16:9. A 4:3 screen needs different width and height geometry.
Should I buy a screen before checking projector specs?
No. Check throw ratio, zoom range, brightness, and mounting requirements for the exact projector first.
Related calculators
- TV Size Calculator
- TV Dimensions Calculator
- Aspect Ratio Calculator
What does this mean?
This calculator is designed to help you understand the likely number before you make a decision or start an application.
Your result should be checked against official UK guidance, especially if your circumstances include dependants, exemptions, prior leave, or a complex immigration history.
Treat the figure as a planning tool rather than legal advice. Where the answer affects an application deadline or major payment, speak to an authorised adviser.
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