When you know the throw ratio of your beamer, you're now ready to calculate how far you need to place your beamer from your screen/wall. Don't worry, it's not difficult.
The basic calculation is:
Distance = throw ratio × image width
Most people have their ideal screen size in mind already. Like they've bought a projection screen of 120 inch, or simply want a 60, 80 or 100 inch projection on their wall. For the most common aspect ratio of 16:9, you can use this easy calculation:
Distance in metres = screen size in inches × 0.0221 × throw ratio
Example:
100 inch screen × 0.0221 × 0.8 throw ratio = 1.77 metres
That means that with a throw ratio of 0.8, your beamer can now be placed 1.8 metres away from your screen/wall to create a 100-inch projection.
Here are some example distances for popular throw ratios:
0.25 Ultra-short Throw:
60 inch: 0.3 m.
80 inch: 0.4 m.
100 inch: 0.6 m.
120 inch: 0.7 m.
0.5 Short-throw:
60 inch: 0.7 m.
80 inch: 0.9 m.
100 inch: 1.1 m.
120 inch: 1.3 m.
0.8 Short throw:
60 inch: 1.1 m.
80 inch: 1.4 m.
100 inch: 1.8 m.
120 inch: 2.1 m.
1.2 Standard/mini beamer:
60 inch: 1.6 m.
80 inch: 2.1 m.
100 inch: 2.7 m.
120 inch: 3.2 m.
These numbers are estimates for a screen aspect ratio of 16:9, which is the most popular format used by mini beamers currently.
For mini beamers, short-throw ratios are very popular due to the fact that it's easier to create a large image from a shorter distance. That means you can use it in smaller rooms. Always make sure to check the exact throw ratio of your beamer, because even a small difference can change the ideal distance.
The moment you know the throw ratio of your beamer, combined with your preferred screen size in inches, means that you're ready to mount or place your beamer at the right distance. This helps you get the perfect image size without guessing or doing it all over again.
