Calculator Form
Example Data Table
| Screen Diagonal | Aspect | Lens Ratio | Approximate Throw Range | Planning Use |
|---|---|---|---|---|
| 100 in | 16:9 | 1.20 to 2.00 | 8.7 ft to 14.5 ft | Small meeting room |
| 120 in | 16:9 | 1.30 to 2.20 | 11.3 ft to 19.2 ft | Classroom |
| 150 in | 16:10 | 1.50 to 2.40 | 15.9 ft to 25.4 ft | Training hall |
| 200 in | 16:9 | 1.70 to 2.80 | 24.7 ft to 40.7 ft | Large venue |
Formula Used
Screen width = diagonal × aspect width ÷ square root of aspect width squared plus aspect height squared.
Screen height = diagonal × aspect height ÷ square root of aspect width squared plus aspect height squared.
Throw distance = effective screen width × throw ratio.
Required throw ratio = desired throw distance ÷ effective screen width.
Lens shift allowance = screen dimension × shift percent ÷ 100.
The effective width includes the overscan allowance. The recommended construction window tightens the result with the selected tolerance.
How to Use This Calculator
- Enter the NEC projector model or lens note.
- Add the screen diagonal and select the aspect ratio.
- Use width or height overrides for known screen dimensions.
- Enter the minimum and maximum throw ratios from the lens guide.
- Choose the output unit used on your drawings.
- Add the desired throw distance for a fit check.
- Add room depth, projector depth, and rear clearance.
- Enter lens shift values for mounting position planning.
- Press Calculate and review the result above the form.
- Download CSV or PDF for site records.
Construction Planning Article
Why This Throw Distance Tool Helps
A projector location can affect every finish in a room. Ceiling grids, cable paths, screen walls, and service zones all depend on the lens position. This calculator gives a practical planning range before final site work begins. It is useful for classrooms, meeting rooms, halls, retail spaces, and small theatres.
Construction teams often receive a screen size before a projector is selected. They may also receive a projector model without a confirmed lens. This tool connects both details. It converts the chosen screen diagonal into width and height. Then it applies the minimum and maximum throw ratios. The result is a lens-to-screen distance range. A desired throw distance can also be checked.
The calculator adds construction controls. Overscan allows a small image margin. Tolerance protects the layout from tight mounting errors. Room depth, projector body depth, and cable clearance show the space left behind the unit. These checks help avoid a mount that fits on paper but fails on site.
How It Supports NEC Installations
Many NEC units offer fixed lenses, zoom lenses, or optional interchangeable lenses. Each lens has its own throw ratio. You can enter the exact ratio from the lens sheet. You can also enter a broad range during early budgeting. The model and lens fields keep the report clear for reviewers.
Lens shift values are included for placement studies. Vertical shift estimates the allowed lens height around the screen center. Horizontal shift estimates sideways movement. These figures are planning aids. Always confirm with the official lens guide before drilling, ordering brackets, or closing ceilings.
Better Field Decisions
A single throw number is rarely enough. Installers need a minimum range, a maximum range, and a safer working window. Designers need screen size checks and aspect ratio checks. Project managers need simple exports for records. This page supplies those outputs in one place.
Use the CSV export for schedules and spreadsheets. Use the PDF export for client notes and site folders. Keep the example table nearby when training staff. It shows how lens ratio changes the possible mounting distance. Careful throw planning reduces rework, protects image quality, and supports cleaner construction coordination.
Share final numbers with installers before ceiling work begins onsite.
FAQs
1. What is throw distance?
Throw distance is the lens-to-screen distance. It tells installers where the projector lens should sit to create the required image size.
2. What is throw ratio?
Throw ratio compares throw distance with image width. A ratio of 1.5 means the lens sits 1.5 screen widths from the screen surface.
3. Can I use this for NEC short throw units?
Yes. Enter the short throw lens ratio from the projector or lens specification. The calculator will adjust the placement range.
4. Why is screen width important?
Throw calculations use image width, not diagonal alone. The tool converts diagonal and aspect ratio into the correct screen width.
5. What does construction tolerance do?
Tolerance narrows the suggested mounting window. It helps avoid a placement that is mathematically valid but too close to the lens limit.
6. What does overscan allowance mean?
Overscan adds a small margin to the image width. It is useful when the image must slightly cover the visible screen area.
7. Should I confirm results with official lens data?
Yes. This calculator is for planning. Always confirm final dimensions with the NEC lens guide before installation work begins.
8. Can I export the calculation?
Yes. Use the CSV option for spreadsheets. Use the PDF option for client notes, field folders, and construction records.