Projector Throw Distance Calculator
Enter your desired screen size and room distance. We'll tell you exactly what throw ratio to shop for — and which projectors in our catalog ship with it.
The single most expensive mistake in projector buying is throw ratio mismatch — choosing a projector before measuring the room. A standard-throw projector in a small living room produces an image too small to be impressive; a long-throw projector in a shallow room physically can't reach the wall. Throw ratio determines the projector category before brightness, resolution, or price.
Throw ratio is the ratio of throw distance to image width. A 1.5 throw ratio means 1.5 feet of projection distance gives 1 foot of screen width — so a 100" (87" wide) image needs 11' of distance. The calculator inverts the math: enter your screen size and the distance from where the projector will sit, and we compute the throw ratio you need.
We then match against real projectors whose throw ratio range covers your target. Most projectors support a zoom range (e.g. 1.2-1.6) rather than a fixed ratio, giving you some placement flexibility. Wider zoom ranges (1.6× or more) are friendlier for retrofits where you can't move the projector mount; narrow ranges or fixed-throw projectors require precise placement. The recommendations also surface brightness (ANSI lumens) and resolution so you can pick by room characteristics, not just throw geometry.
Your setup
Throw distance is from the projector lens to the screen. Measure flat — if you're shelf-mounting or tabletop, that's where the lens will sit.
Required throw ratio
100" screen at 10' distance
Throw ratio
1.38:1
Look for projectors with throw ratio 1.28–1.48 (or zoom range covering that).
Screen width
87.2"
Screen height
49"
Projectors that match a 1.38:1 throw
Sorted by closest throw-ratio match to your setup.
ViewSonic
ViewSonic LS741HD 5000 Lumens 1080p Laser Projector with H/V Keystone, 4 Corner Adjustment, 360 Degree Projection, 1.6X Optical Zoom, LAN Control, and 24/7 Operation
ViewSonic
ViewSonic LX700-4K 3500 Lumens 4K Laser Projector, 240Hz and 4.2ms for Smooth Home Entertainment, 1.36x Optical Zoom, H/V Keystone, and 360-Degree Projection for Flexible Setup, and Dual HDMI Inputs
![[1500 ANSI/Google TV/Voice Control]Smart Projector with WiFi 6 and Bluetooth, 4K Support, Outdoor Movie Proyector, 1080P Home Ceiling Auto Focus Projector, PUTRIMS K12 Gray](https://m.media-amazon.com/images/I/51uIa2p0JqL._SL500_.jpg)
PUTRIMS
[1500 ANSI/Google TV/Voice Control]Smart Projector with WiFi 6 and Bluetooth, 4K Support, Outdoor Movie Proyector, 1080P Home Ceiling Auto Focus Projector, PUTRIMS K12 Gray
How this calculator works
What is a projector throw ratio?
Throw ratio is the distance from the projector lens to the screen, divided by the screen width. A throw ratio of 1.5 means 1.5 feet of distance produces 1 foot of screen width. Lower throw ratio = projector can sit closer for the same screen size. Ultra-short-throw projectors (<0.4) can sit inches from the wall; long-throw home theater projectors need 15+ feet for a 100" image.
How do I measure for the calculator?
Screen diagonal is corner-to-corner (a 100" screen is 100" diagonal). Throw distance is the straight-line distance from where the lens will physically sit to the screen surface. Don't guess — measure with a tape or laser distance tool. For ceiling mounts, the relevant distance is from the ceiling-mount position, not from where you'd set it on a shelf.
What's the difference between short, standard, and long throw?
Ultra-short throw (<0.4): projector sits inches from the wall — great for living rooms with limited depth. Short throw (0.4–1.0): 3-6 feet for a 100" screen. Standard (1.0–2.0): typical home theater, projector behind the seating. Long (2.0+): mounted at the back of a large room or auditorium.
My projector has a throw ratio range, not a single number — what does that mean?
Most projectors have an optical zoom lens, so they support a range like "1.2:1 – 1.6:1". As long as your required throw ratio falls within that range, the projector will work; you adjust the zoom to dial in the exact screen size. Wider zoom ranges (1.6× or more) give more placement flexibility — useful if you're not sure exactly where the projector will live.
How does brightness (lumens) interact with throw?
Throw is geometry; brightness is light output. Longer throw distances don't reduce brightness (the light cone is the same regardless of distance), but they do affect perceived brightness because the image is spread over the same area regardless of distance. The key brightness numbers: 1500+ ANSI lumens for dark rooms, 2500+ for ambient light, 3500+ for a bright living room.
What's the difference between ANSI lumens and other lumen claims?
ANSI lumens use a standardized 9-point measurement across the image and a specified contrast. Marketing lumens, "LED lumens," "ISO lumens," and other variants can be 2-3× higher than the equivalent ANSI rating, making cheap projectors look brighter than they are. Always look for the ANSI number; if it's not listed, assume the claim is inflated.
Do I need a special screen?
Not necessarily for dark home theaters — a white wall works surprisingly well. For ambient-light rooms, an ALR (ambient light rejecting) screen reduces washout dramatically. UST projectors need a UST-specific screen because they project at sharp angles that confuse standard screens. Budget $150-500 for a quality screen; it matters as much as the projector.
How important is keystone correction?
Use it only as a last resort. Keystone correction compensates for off-axis projection by digitally squashing the image, which costs you resolution and sharpness. Best practice: physically align the projector so the lens is centered horizontally and at the right vertical offset. Lens shift (mechanical) is much better than keystone (digital).