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Will a BenQ TH575 fit your room? Check lens distance, image size and height
Use documented TH575 geometry to rule out a poor fixed-shelf position before buying. Optical size is only one check; wall height, ventilation and exact India unit eligibility still matter.
Measure from the lens to the wall, not from the back of the shelf. At 10 feet, the TH575’s documented throw-ratio range gives roughly 84–92 inches diagonal for a 16:9 image. That calculation does not establish safe installation, brightness, focus quality or seller warranty eligibility.
Measure the usable space
- Measure perpendicular lens-to-image distance, allowing for the projector body and its required operating clearance.
- Measure usable wall width and height, excluding furniture, doors and obstructions.
- Record lens height relative to the bottom of the proposed image. A width calculation does not establish vertical fit.
- Check stable horizontal support, ventilation, power, signal cable and access under the exact manual. Do not infer suitability from an attractive shelf photo.
The TH575 India specifications list 1.49–1.64 throw ratio, 16:9, 1.1× optical zoom and 108% offset. Body dimensions are 296 × 120 × 221 mm; those dimensions are not the complete operating space. The exact TH575 user manual, version 1.01 provides the projection-distance table and placement instructions used below.
Calculate the horizontal fit
For this 16:9 example: image width = lens distance ÷ throw ratio; height = width × 9 ÷ 16; diagonal = width × √337 ÷ 16. Divide metres by 0.0254 for inches. Use the full ratio range rather than treating optical zoom as unlimited resizing.
On small screens, scroll the table sideways.
| Lens-to-wall distance | Calculated image width | Calculated diagonal | Decision for the stated example |
|---|---|---|---|
| 60 inches / 1.524 m | 0.929–1.023 m | 41.98–46.20 inches | Does not reach an assumed 55–75-inch target |
| 10 feet / 3.048 m | 1.859–2.046 m | 83.95–92.40 inches | On an assumed 2 m-wide wall, only part of the zoom range fits horizontally |
The 10-foot example gives an image about 1.045–1.151 m high. A nominal 2 m wall is a hypothetical clear rectangle, not a measurement of your room. Leave room for any border and verify the chosen size with the manual and real measurements. These are geometric calculations, not projection tests.
Check image height against the manual
The manual’s 90-inch row gives 1992 × 1121 mm image dimensions, lens distances 2969–3268 mm and a 90 mm bottom offset for the upright placement shown. Its 100-inch row gives 2214 × 1245 mm, 3299–3631 mm lens distance and 100 mm offset. Use those rows and the orientation diagram; do not guess offset by multiplying a diagonal by 108%.
A 9.5-foot lens distance is 2895.6 mm, shorter than the 90-inch row’s 2969 mm minimum. Ten feet (3048 mm) and 10.5 feet (3200.4 mm) are within that row’s horizontal distance interval. Neither establishes that the image clears your furniture or fits vertically. Digital correction is not a substitute for checking the optical and physical placement.
Leave the operating space the manual requires
The TH575 manual requires stable horizontal placement, free airflow and at least 50 cm clearance from walls. Do not block ventilation with bedding or other soft materials, and do not look into the operating lens. Account for the body and connections as well as this space when judging a shelf. The documented box contents do not make an HDMI cable or streaming source part of a complete setup; confirm the exact package.
Keep India warranty policy separate from unit eligibility
BenQ’s TH575 India warranty page, checked 16 October 2026, publishes projector terms of 24 months from invoice or 27 months from manufacture, whichever ends first. For current purchases, its lamp limit is 12 months or 1,000 hours, whichever comes first. Coverage is qualified by authorised purchase and import/marketing by BenQ India; overseas projector warranties are excluded. This establishes the published policy, not eligibility for a particular seller’s unit. Keep the invoice, manufacture date and seller/importer details with the quote.
Use the result as a placement decision
- If the measured distance cannot produce the target size, change the position or target before spending.
- If horizontal size works, check the vertical offset, usable wall, safe support and ventilation next.
- If those checks pass, confirm today’s exact India seller, unit eligibility, package and price. No present buying recommendation follows from geometry alone.
This guide covers the documented TH575 example only. It makes no Arc7 or MoGo4 placement claim, no brightness comparison and no hands-on performance claim.