OLED technology uses organic (carbon-based) materials, instead of semiconductor (e.g., Silicon, Indium) materials used by standard LEDs. Each pixel of an OLED display comprises a red, green, and blue diode (Figure 1) which emit light when a voltage is applied to them. Each diode can be switched on and off in different combinations and with different intensities to illuminate pixels, which then combine to create images on a screen.

Assuming the screen's length is the arc length of a circle, we can find the base depth and width by using the following formulas which we use in the screen size calculator:

Let's say we want to compare two smartphones: The Apple iPhone X with a 5.85-inch display, and the iPhone 8 Plus, which has a 5.5-inch screen. We could expect that the former would have a bigger screen, but we can't forget about aspect ratios! iPhone X has a narrower screen with a 2.17:1 ratio, and iPhone 8 Plus has a standard 16:9.

The diodes in displays made with OLEDs emit light when a voltage is applied to them. The pixel diodes are selectively turned on or off to form images on the screen. This kind of display can be brighter and more efficient than current LCD displays.

The value 5.8-inch stands for the diagonal of the screen. To check whether that smartphone will fit in your pocket, you will need to know one more parameter — the aspect ratio, the width, or the screen's height. In our example, let's assume we know the aspect ratio, and it is equal to 16:9:

If you want to find the ideal size of your TV or its distance from your eyes, check out this TV size calculator. Another useful tool is this great projector calculator, which can help in fulfilling your dreams about a home cinema.

Repeat the steps for iPhone 8 Plus, choosing a 16:9 aspect ratio and 5.5-inch diagonal. And what do you get? 4.8" for screen width, 2.7" height, and 12.93 in² screen size.

Our screen size calculator offers the possibility to estimate both a flat and curved screen size. As we've already learned how to proceed with a flat monitor, let's see the differences for a curved one.

The screen size calculator can help you determine the screen dimensions. Have you ever wondered what the statement, the diagonal of the screen is equal to 40" means? How much space does it take up on the wall? What are its height and width? Here, you can determine the monitor size or phone screen dimensions. If you're curious enough, you can even determine how to measure a curved TV screen size!

So even though the first iPhone has a longer diagonal, the screen size is almost the same as iPhone 8 plus'. In other words, although the iPhone X's diagonal is 6.3% longer, its area is only 0.5% bigger (iPhone X also has a big cutout and curved edges, but we are not taking them into account — even with that simplification, the screen area is still very similar).

The aspect ratio is the relationship between the height and width of a rectangular display. Every device with a screen uses that value — your laptop, smartphone, tablet, monitor, or projector. However, it doesn't tell you how big a screen is. It only explains the proportion between the height and the width.

How do I measure a curved TV screen size, then? — you may ask. To evaluate the screen's length, height, and area, we can follow the same equations as for a flat one:

The main advantage of OLED technology is that it allows displays to be much thinner (up to 10x) than displays made using LCD technology (with WLED backlight). Another important advantage is that because OLED displays do not need a backlight, they consume less power. This is critical for battery-powered displays (e.g., smartphones) as it means the battery does need to be charged as often. However, some disadvantages of OLED displays are that they are less water-resistant and the colors they produce deteriorates over time.

The crucial geometric difference between the curved and flat monitor is that the curved one occupies more space perpendicular to the screen from a user's point of view while being a little narrower. We call these dimensions depth and width, respectively. To avoid confusion, we can depict all essential measures in a single picture.

The size of a 16:9 screen depends on how long the screen's diagonal is, as 16:9 is merely the ratio of the screen's width to its height. If you have the screens diagonal, you can multiply that measurement by 0.872 to get the screen's width. You can also multiply the diagonal by 0.49 to get the screen's height. Then, if you wish to find the screen area, multiply the width by the height.

The basic characteristics of a curved screen are a diagonal, an aspect ratio, and a curvature rating. You can measure the diagonal of a curved monitor analogously to a flat one. The only thing you need to remember is to touch the screen with a measuring tape. The curvature rating tells about the radius of a circle that encompasses the screen. Typically, the producers provide the curvature rating in millimeters, so 1800R denotes the monitor that fits inside the circle of a radius equal to 1800 mm. Take a look at the image to compare curved screens of different curvature ratings.

Great! Now we know the screen area and how tall and wide it is. The screen size calculator is here for you to calculate it right away.

Adena Benn is an Information Technology teacher with a degree in Computer Science. She has been teaching high schoolers since 1996 and loves everything computers. She loves problem-solving, so creating calculators to solve real-world problems is her idea of fun. She writes children's stories, is a seamstress, and is an avid reader. In her spare time, she travels and enjoys nature. See full profile

A physicist at the Institute of Nuclear Physics in Kraków. Currently looking for that one and only magnetic nanomaterial that will improve everyone's life. Interested in astronomy and likes playing board games. Also, fond of watching chess tournaments; he never refuses to play a game (or two) himself. See full profile

WLED (white light emitting diode) is a term usually associated with television and mobile phone LCD displays. Although WLED is marketed as being in some way “different” or “superior” to standard LEDs, WLED and LED technology are identical using semiconductor materials. The white light produced is used as a ‘backlight’ for LCD displays and is created by applying an electric field to a blue (or UV) LED and then filtering the emitted light through a material of a different colour (e.g., a yellow phosphor). The combination of the light and filter create (almost) white light. In an LCD display, this light is then polarized using arrays of many liquid crystals, which operate under the influence of variable electric fields to create images on a screen.