HT Designer

Tools for the A/V Pro


VideoCalc is The tool that will help you design Home Theaters in a consistent, quick and easy way.
It makes all the tedious calculations a breeze and ensures you can get the desired information in an intuitive way.

This is a must have for Home Theater enthusiasts, custom installers, video professionals and more.

Get it on Google Play

VideoCalc is made up of several tools, that each in their own right provide you with essential calculations but do work together, ensuring the effect of every component on the system is taken into account.

The tools are organized in a natural progression, guiding you through the process of designing a Home Theater that follows the industry best practices and standards.


The screen tab helps you compute the dimensions of your screen (i.e. diagonal, width, height) and select its aspect ratio.
As those 4 values are linked together, setting 2 of them will automatically define the other 2.

To edit any of the diagonal, width or height, tap on its value (blue text), a numeric keypad will appear. Enter a value and tap ‘Done’. The other 2 dimensions are re-calculated.
The surface of the screen is also calculated and displayed inside the graph below.

The aspect ratio is never automatically calculated for you.


You select the aspect ratio by tapping on it. A selection list with the most commonly used ratio is displayed. Simply tap on the desired aspect ratio.

When changing the aspect ratio, the height is considered fixed. The width and diagonal are re-calculated based on the newly selected aspect ratio.

The graph is also updated, displaying a screen with the corresponding aspect ratio.


In addition to being used standalone to help you find the appropriate screen size, this tab is the basis for most of the other ones, as it defines the screen size that is used in the throw ratio, luminance and viewing angle tabs.


This tab makes the most sense for projection based systems, where the aspect ratio of the projector matrix can vary and be different from the aspect ratio of the screen used. An anamorphic lens can also be used as part of the system.

The tool shows you how the projected image will fit within the defined screen and the deformation that the anamorphic lens would apply to it.
This is a fantastic tutorial tool to understand anamorphic systems.

Parameters defined in this tab are taken into account for the throw ratio calculation and so does not apply for flat panels.


The application always ensures that the biggest possible projected image fitting the screen as a whole is used.

In particular this means that on a 16:9 screen, a 16:9 projector image will fill the entire screen. If an anamorphic lens is added to the system, the image will fill the screen width and black bars will be added on the top and bottom of the screen.

This in turns means that the projector must be placed closer to the screen in that configuration.


Throw ratio

This tab helps you validate if a given projector can work with your screen and where to place it.
If you already know the projector to be used, enter its minimum and maximum throw ratio and the tool indicates where the projector can be positioned (based on the informations defined in the first 2 tabs).

If you want to select a projector based on your possible set-up, enter the minimum and maximum distance from the screen the projector can be located and the tool computes the minimum and maximum throw ratio that will work. Any projector with a throw ratio that can be set in that range should work (always take some security margin !).

All computations use the information defined in both the Screen and the Geometry tab.


The graphical representation is provided as an illustration of the possible distance variation. It is not up to scale and in particular the projector beam is not representative of reality. You can drag the projector on the graphic to display any intermediate distance.
To get a bigger graphical representation, rotate your device to landscape orientation.


Important note: there is always a difference between the specifications of a projector and the actual physical values. Use this information as a guide only and double check with the projector before any permanent installation.


The Luminance tab allows to find out how big the screen can be with a given projector or how bright your projector must be to light up the defined screen, while respecting the industry best practices.

The target luminance as recommended by SMPTE is 16 fL.

The screen size used is the one defined in the Screen tab.

Note that the actual projector output can be smaller than the one specified. It will also lessen as the bulb ages.


Viewing angle

Compute the horizontal viewing angle for a viewer sitting at a given distance or the seating distance required to sustain a given viewing angle.

The screen used is the one defined in the Screen tab. The angle is computed for the full width of the screen, so bear in mind that the actual viewing angle will be less when using content that does not fill the entire screen width.

SMPTE viewing angle recommandation is 30°, whereas THX recommandation is 36° minimum for the front row and 26° minimum for the back row.



VideoCalc works in both imperial and metric units.

On any tab, swipe the screen down to reveal the units selection view, giving you the choice between centimeters, meters, inches and feet.

Current values will be converted as you switch between units.


Getting help

Alongside the unit selection, a help button is available on every tab.
This provide you with key information on how that tab works.

Should you require any additional information, or make suggestions on how to improve the product, please contact support [at] htdesigner [dot] eu