Advanced options
Screen sizes are always the diagonal of the visible display, excluding bezels; add a couple of centimetres each way when checking whether a TV fits a space.
What The Screen Size Calculator Works Out
- Width: the diagonal split by Pythagoras according to the aspect ratio. For 16:9, width is about 87% of the diagonal, so a 55 inch TV is roughly 122 cm wide before the stand and bezels.
- Height: the matching vertical dimension, about 49% of the diagonal for 16:9 (a 55 inch TV is about 68 cm tall). Both are shown in centimetres with inches underneath.
- Screen area: width times height in cm2. Area grows with the square of the diagonal, so a 65 inch TV has about 40% more screen than a 55 inch, and an ultrawide of the same diagonal as a 16:9 monitor is wider but has less total area. Comparing areas is the honest way to weigh screens of different shapes.
- Custom ratio (advanced): enter any width:height pair, such as 3:2 for Surface-style laptops, 5:4 for older monitors or 1:1 for a square display, instead of the five preset shapes.
- Pixel density (advanced): the diagonal pixel count divided by the diagonal in inches. 1080p at 24 inch is 92 PPI, QHD at 27 inch is 109 PPI and 4K at 32 inch is 138 PPI; below about 70 PPI text looks soft on a desk, which is why a 43 inch 1080p TV makes a poor monitor.
- Viewing angle at your distance (advanced): how many degrees of your vision the width fills from the distance you enter. Under 20 degrees feels small, 30 degrees is the SMPTE cinema recommendation and 40 degrees the THX immersive figure. The sub-line also gives the distance beyond which 20/20 eyes can no longer pick out individual pixels.
- Compare with another diagonal (advanced): the percentage difference in area between your screen and a second size of the same shape, plus that screen's dimensions, for settling 27 versus 32 inch or 55 versus 65 inch.
- Outer size with bezels (advanced): adds a frame allowance on every edge to give the footprint that actually has to fit the alcove or desk. Modern TVs have 0.5 to 1.5 cm bezels; monitors with a thick chin may need more at the bottom.
- Common sizes table (advanced): width, height and area for nine standard diagonals from 24 to 85 inches at your chosen ratio, each shown as a percentage above or below your screen.