Projector Throw Ratio Calculator
Calculate the ideal distance or screen size for your projector setup.
Your Calculated Throw Ratio:
Understanding Projector Throw Ratio
The throw ratio is a critical specification for any projector. It determines how large an image will be at a certain distance from the screen. Without understanding this ratio, you might purchase a projector that produces an image too large for your wall or too small for your room.
The Throw Ratio Formula
Calculating the throw ratio is straightforward physics. You only need two measurements in the same units (both in inches, both in feet, or both in meters):
Throw Ratio = Throw Distance / Image Width
Types of Projector Lenses
Based on the calculated ratio, projectors are generally categorized into three main types:
- Ultra Short Throw (UST): Ratio less than 0.4:1. These sit directly against the wall.
- Short Throw: Ratio between 0.4:1 and 1.0:1. Ideal for small rooms or gaming.
- Standard/Long Throw: Ratio greater than 1.0:1. Most common for ceiling mounts in large rooms.
Real-World Examples
| Scenario | Distance | Image Width | Ratio |
|---|---|---|---|
| Home Cinema (Standard) | 12.0 ft | 8.0 ft (approx. 110″ diag) | 1.50:1 |
| Gaming Setup (Short Throw) | 4.5 ft | 6.0 ft (approx. 82″ diag) | 0.75:1 |
| UST Living Room | 1.5 ft | 7.5 ft (approx. 100″ diag) | 0.20:1 |
Why Image Width Matters Over Diagonal
Projector manufacturers define throw ratio based on horizontal width, not the diagonal measurement. If you only know your screen's diagonal size, you must first convert it to width based on the aspect ratio (usually 16:9 for modern projectors) before using this calculator for precise installation.