Projector Throw Calculator — Frequently asked

Throw ratio is the projector's distance from the screen divided by the image width. A throw ratio of 1.5 means the projector sits 1.5m back for a 1m wide image. A zoom lens lets you trade focal length for image size at a fixed distance — at the wide end of the zoom (small throw ratio), you can sit closer for a given image; at the long end (large throw ratio), you sit further. The Sony VPL-XW7000ES at 1.35-2.16 means for a 2.5m wide image (~115″ 16:9), the projector can sit anywhere from 3.4m to 5.4m back. That two-metre range is real placement flexibility — exploit it at the architectural drawing stage rather than locking a mount point and discovering later that the projector cannot reach. UST projectors have a single throw ratio (typically 0.16-0.25) because the lens is fixed; for those, the placement answer is precise but the wall-flatness tolerance is unforgiving.

Lens shift is the projector's ability to optically shift the projected image up, down, left or right of its optical axis without geometric distortion. A projector with 100% vertical shift and 50% horizontal shift can be mounted at the ceiling well above the screen centre, or pushed against a side wall, and still project a rectangular image without keystone correction. A projector with 0% shift forces the mount onto the screen's perpendicular axis — any deviation triggers digital keystone, which crops the image and discards pixels (you specified 4K, you receive 3.6K or worse on the corners). For ceiling-mounted home cinema in a real room with real architectural constraints, lens shift is the most under-appreciated specification. Premium SXRD/D-ILA projectors (Sony VPL, JVC DLA-NZ) carry ±36% horizontal and ±85-100% vertical — generous envelopes that let the mount sit discreetly above the seating row. Budget 4K projectors often carry ±10% vertical and 0% horizontal — useful only when the mount can sit on the perpendicular.

Three resolution stories matter. (1) Native 4K = 3840×2160 or 4096×2160 (DCI) pixels physically present on the imaging panel. Sony SXRD, JVC D-ILA BLU-Escent and 3DLP cinema projectors are genuinely native. (2) Pixel-shifted 1080p = a 1920×1080 panel that vibrates between two positions 60 times per second to perceive as 4K. Epson 4K-PRO UHD, BenQ HT3550, Optoma UHD55 — engineering shortcut that delivers ~80% of the perceptual benefit at a small fraction of the cost. (3) DCI 4K = 4096×2160, an extra 256 pixels wide for cinematic aspect handling. For a 130″+ screen at <5m viewing, native 4K is visibly better than pixel-shifted on bright scenes with fine detail. Below 100″ at 4m+, the gap closes. The calculator's pixel-density (PPD) figure makes this concrete: at 60 PPD or above, the projector resolves at the human retinal limit; below 30 PPD, pixel structure is visible on bright content.

Three engines, three cost-of-ownership patterns. Lamp engines (UHP mercury or xenon) deliver 2,000-4,000 hours to 50% brightness, then need replacement (₹15-40k typical). Strong colour accuracy out of the box, predictable performance, lowest sticker price. Laser-phosphor engines run a blue laser through a spinning phosphor wheel to generate white light — 20,000 hours to 50% brightness (so an 18-year curve at 3 hours/day), no consumable replacement, instant-on, slightly compromised colour gamut (yellows can be pushed). Tri-laser RGB engines use three separate red/green/blue lasers — widest colour gamut (covers BT.2020 or close to it), excellent black levels, 20,000+ hour life. The premium engine in 2026 home cinema. Tri-laser carries a colour-speckle artefact some viewers see; most projectors mitigate it well. For a frequently-used home cinema, laser-phosphor or tri-laser pays back the price premium inside the first refresh cycle.

Because the projector throws light, and what the audience sees is light reflected back off the screen surface. Three screen attributes matter. (1) Gain — measured against a unity reference (1.0 gain matte white). A 1.0 gain screen reflects light evenly in all directions; a 1.2 gain screen reflects more on-axis but less to the sides; a high-gain (1.4-1.8) ALR screen reflects most light directly at the seating sweet spot. (2) Surface — matte white is the reference for treated dark rooms; grey screens absorb ambient light for better contrast in mixed rooms; ALR (ambient-light rejecting) screens are micro-structured to reflect projector light to viewers while rejecting room light. (3) Acoustically transparent — perforated or woven screens let L/C/R speakers sit behind the panel for cinematic dialogue alignment; they cost ~10% light to perforation. A 3000-lumen projector on the wrong screen looks worse than a 2000-lumen projector on the right screen. The calculator's brightness warning surfaces this failure mode.

The calculator is only as accurate as the verified data behind it. v1 carries 30 marquee models across 14 brands, each cited to a manufacturer datasheet URL with a retrieval date. If your projector is not in the list, the calculator cannot help — projectors with very different throw envelopes (short-throw vs UST vs long-throw) need genuine spec verification, not estimation. We add verified models in editorial batches. Send the model name and the datasheet URL via the contact form; we re-verify and re-publish on an annual cycle, bumping the verifiedAt date so users can judge data freshness.

No. It is a brief-stage scoping tool. It answers 'can a Sony VPL-XW7000ES throw 130″ in this room with this aspect ratio'. It does not measure your actual room, your actual ambient light, your actual ceiling-joist availability, your actual cable conduit pathway. For a serious project, the calculator's outputs are the brief; a site survey, drawings review and an integrator-led commissioning plan are the design. The advisory text on the calculator page is explicit: indicative outputs intended to scope an early-stage conversation. Final figures must be validated against the actual site survey, applicable codes and the project drawings.