Projector Throw Distance Calculator
Calculate throw distance, screen size or the ratio your room needs. Check lens placement, wall width and image height in one plan.
Use your model’s optical specifications. Leave maximum blank for a fixed lens. Values shown are an example.
Image aspect ratio: 16:9 · m
Your projection plan
- Lens distance range
- 3.19–3.98 m
- 10.46–13.07 ft
- Image width × height
- 2.66 × 1.49 m
8.72 × 4.9 ft
Check your room
Measure from the screen plane. Rear allowance includes the body behind the lens, ventilation and cables; use your model’s requirements. Wall width means usable image space, excluding the frame.
Part of the zoom range fits
Usable lens positions: 3.19–3.8 m / 10.46–12.47 ft
Plan the screen height
- Image top above floor
- 2.19 m / 7.2 ft
- Image center above floor
- 1.45 m / 4.75 ft
- Space above image
- 0.31 m / 1 ft
This locates the image, not the projector lens. Add frame clearance. Ceiling-mount drop and lens height require your model’s offset/lens-shift diagram.
Distance examples for your throw ratio
Select a diagonal to use it in the calculator.
| Image diagonal (inches) | Lens distance range |
|---|---|
| 2.13–2.66 m / 6.97–8.72 ft | |
| 2.66–3.32 m / 8.72–10.89 ft | |
| 3.19–3.98 m / 10.46–13.07 ft | |
| 3.98–4.98 m / 13.07–16.34 ft |
Geometry estimate, not an installation certification. Confirm the model’s distance table, optical zoom and native image format.
Read the projector installation guide →Three calculations, one set of measurements
Find distance starts with an image diagonal and the optical throw-ratio range. Find screen size reverses the calculation from a measured lens distance. Find throw ratio tells you what lens ratio a chosen image and position require; it does not identify compatible projector models. Changing modes preserves your inputs.
The throw-distance formula
Distance = image width × throw ratio. For a 120-inch 16:9 image, width is about 2.657 m. A 1.2–1.5 lens therefore needs about 3.19–3.98 m. Divide distance by the maximum ratio to find the smallest image, and by the minimum ratio for the largest. These are rounded geometric estimates.
Read the room and height checks
Measure from the screen plane. Rear allowance includes the body behind the lens, ventilation and cables; use your model’s requirements. Wall width means usable image space, excluding the frame.
This locates the image, not the projector lens. Add frame clearance. Ceiling-mount drop and lens height require your model’s offset/lens-shift diagram.
Room checks cover image geometry and the space you entered. Test the real projector before fixing the mount.
Use the specifications for your projector
Geometry estimate, not an installation certification. Confirm the model’s distance table, optical zoom and native image format.
Very short throw: lens-based arithmetic does not locate the cabinet or screen height. Use the exact model’s installation drawing.
FAQ
Is throw distance measured from the wall or the lens?
Measure from the screen plane. Rear allowance includes the body behind the lens, ventilation and cables; use your model’s requirements. Wall width means usable image space, excluding the frame.
Does this calculate the exact ceiling-mount height?
This locates the image, not the projector lens. Add frame clearance. Ceiling-mount drop and lens height require your model’s offset/lens-shift diagram.
Can I use this for an ultra-short-throw projector?
Very short throw: lens-based arithmetic does not locate the cabinet or screen height. Use the exact model’s installation drawing.