Projector Size Calculator
Enter the screen diagonal, the aspect ratio and your projector's throw ratio, plus the top of its zoom range if it has one. The calculator gives the distance from lens to screen, the screen width and height and where to sit.
- Throw distance
- Screen width
- Seating distance
Throw ratio is in the projector's specifications, often given as a range for zoom lenses.
Throw distance is the throw ratio times the screen width. A 100 inch 16:9 screen is 87 in wide. A projector with a throw ratio of 1.5 must sit about 3.3 m from it. A short throw projector at 0.5 needs just 1.1 m.
Throw distance chart
16:9 screens. Search for a screen size.
| Screen (in) | Width (cm) | Ratio 0.5 | Ratio 1.2 | Ratio 1.5 | Ratio 2.0 |
|---|---|---|---|---|---|
| 60 | 133 | 0.66 | 1.59 | 1.99 | 2.66 |
| 80 | 177 | 0.89 | 2.13 | 2.66 | 3.54 |
| 100 | 221 | 1.11 | 2.66 | 3.32 | 4.43 |
| 120 | 266 | 1.33 | 3.19 | 3.98 | 5.31 |
| 135 | 299 | 1.49 | 3.59 | 4.48 | 5.98 |
| 150 | 332 | 1.66 | 3.98 | 4.98 | 6.64 |
Distance in metres.
Screen size and distance
16:9, throw ratio 1.5. Slide the screen size.
The side view shows the projector, its beam and the screen.
How to place a projector
Screen to lens. Step through it.
Screen size
Diagonal.
Ceiling mounts need the lens offset as well as the distance, so check the manual.
Standard, short or ultra short throw
Lens types. Compare them.
Ratio over 1.
Ratio 0.4 to 1.
Under 0.4.
Ultra short throw projectors sit right under the screen and need a very flat screen surface.
Before mounting
Projector checks. Tick each item.
Tick each item as you go.
Brightness matters too. Bigger screens need more lumens for the same picture.
What you get
Projector placement. Each tile explains one result.
Lens to screen.
Screen.
Screen.
Best spot.
Type.
For a cinema feel, sit about 1.2 to 1.6 times the screen width away.
Frequently Asked Questions
No question matches that search.
How far should a projector be from the screen?
Multiply the throw ratio by the screen width. With a ratio of one point five and an eighty-seven inch wide screen, about three point three metres.
What is throw ratio?
The distance from the lens to the screen divided by the image width.
How wide is a hundred inch screen?
About eighty-seven inches, or two point two metres, at sixteen by nine.
What is a short throw projector?
One with a throw ratio below about one, so it can sit close to the screen.
Where should I sit?
About one point two to one point six times the screen width away.
Can I use zoom to adjust the size?
Yes. A zoom lens lets you place the projector anywhere in its throw range.
Does aspect ratio change the distance?
Yes, because it changes the screen width for the same diagonal.
Fill the screen first time
Work out the throw distance before drilling the ceiling, and the picture fills the screen exactly.
More size calculators
Each one has its own calculator, worked examples and answers to common questions.