OffAxis projector placement calculator

Loading the calculator…

How to work out where your projector goes

OffAxis is a free online calculator for anyone choosing a projector or planning where to put one. Enter your screen, room and projector model and see straight away how far from the screen and how high it can go for a square picture: no keystone correction, no loss of sharpness.

What it calculates

  • Throw distance for your screen size, from the throw ratio and zoom range of your model.
  • Mounting height: on a table, on a shelf behind the sofa or on the ceiling, upside down included.
  • Vertical and horizontal lens shift. The calculator knows that shifting sideways leaves less shift for height and vice versa, which spec-sheet percentages do not tell you.
  • How far off the screen centre you can place the projector.
  • Picture brightness in a dark or lit room and the viewing angle from your seat.
  • Projector matching for your room and a side-by-side comparison of two models.
  • Installer report as PDF and PNG: side and top drawings with every dimension.

How to use it

  1. Pick a projector from the catalogue or enter your model's specs from the manual.
  2. Set the screen size, the room dimensions and how high the screen hangs.
  3. Drag the projector in the 3D scene to where you want it, or type in the distances.
  4. A green beam means a square picture. If the shift runs out, the calculator tells you where and how far to move the projector.

FAQ

How do I calculate projector throw distance?

Multiply the image width by the throw ratio from the projector specs. With a ratio of 1.2 and a 2.2 m wide screen, the lens should sit about 2.6 m from the screen. With a zoom lens any distance within the range works: the calculator shows its limits for your screen size.

How high should I mount a projector?

It depends on lens shift. Without shift the picture sits in a fixed position relative to the lens, usually with its bottom edge at lens level or slightly above. So on a table the lens goes roughly level with the bottom of the screen, and on the ceiling (upside down) level with the top. With lens shift you get a whole band of heights, and the calculator draws it right in the room.

What is lens shift?

Lens shift moves the picture up, down or sideways optically, without turning the projector. Unlike digital keystone correction it keeps the image sharp. But both axes share one range: the picture has to stay inside the image circle of the lens, so the further it is shifted sideways, the less it can move vertically.

Can a projector sit off to the side of the screen?

Yes, if it has horizontal lens shift and enough of it. The calculator shows how far from the centre you can go at the chosen height. Without it you would have to angle the projector and fix the picture with keystone correction.

What is wrong with keystone correction?

Digital keystone squeezes the picture in software: part of the pixels go unused, sharpness drops, diagonal lines get jagged and some models add input lag. It is better to place the projector so you never need it.

Which projectors are in the catalogue?

Hisense and Vidda, XGIMI, Dangbei, JMGO and Epson, with specs from official sources. If your model is missing, add it yourself: you need the throw ratio and the lens shift range from the manual.

Is it free?

Yes. It runs in the browser with no sign-up and, after the first visit, even offline. Your room and settings stay on your device, and you can share a scene by link. Metric and imperial units are supported.

OffAxis 1.0.0 · Русская версия