What Is an Aspect Ratio on TV and How Does It Work?

If the black bars on your new TV sound familiar, welcome to a massive club. Many people look forward to getting a new TV to watch their favorite movies and shows only to get the annoying bars at the top and bottom or sides of the screen ruining their viewing enjoyment. 

However, this issue is easily manageable, but to understand the problem and decide whether solving it is worth it, you need to know what an aspect ratio is and how it works. Now you may ask yourself, "What is an aspect ratio on TV?" and wonder what aspect ratios have to do with black bars framing the video image on your TV screen. Read on to find out.

Aspect Ratio Definition

The aspect ratio is the width-to-height ratio of a display. It defines the overall shape of the screen and is usually presented as W:H, where W is the width and H is the height. Televisions have had different aspect ratios since their first appearance, so let's review some common aspect ratios over the years.

Common Aspect Ratios

Here are three of the most popular aspect ratios we’ve seen on the market in the past 30 years:

4:3 

The old traditional TVs had a 4:3 TV aspect ratio, meaning that for every four units of width, there were three units of height. It was also called "standard definition" or SD. The images on these TVs looked somewhat boxy because they weren't as wide as the newer models.

16:9

The aspect ratio of many current TVs is 16:9. This is the widescreen HDTV format and is also called "rectangular" or "anamorphic." 

The images on 16:9 televisions are wider compared to 4:3 TVs. As such, you're likely to see black bars framing the picture when watching movies and shows filmed before the 16:9 aspect ratio was introduced.

16:9 TV aspect ratio is today's most common ratio,  used for 4K and 1,920×1,080 resolutions. 

21:9

21:9, also called "ultra-wide," made its debut in 2009. These TVs are even wider than 16:9, so black bars will be noticeable when watching movies not filmed at the 21:9 aspect ratio.

The Relation Between Aspect Ratio and Resolution 

As we mentioned, the aspect ratio of a TV refers to the width and height of the screen, expressed as a ratio. For example, a 16:9 aspect ratio means that the screen's width is 16 units wide, and the height is nine units high. 

And this widescreen aspect ratio is derived from the 1,920x1,080 resolution (1,920/120=16; 1,080/120=9), which defines how many pixels make up the entire screen on your TV. That's how you can calculate (precisely or nearly) any other TV screen aspect ratio by using resolution. 

For further examples, refer to the following table:

The resolution and screen size relationship is also interesting to know consider when choosing a smartphone for watching shows and movies.

Now that we answered the question "What is a TV aspect ratio?" let's see how you can solve typical problems related to your watching content in ratios different from the native one on your TV.

Aspect Ratio Issues

Now, we get to the part that probably brought you to this page in the first place - how to fix the appearance of black bars around your widescreen TV image. Before we dive in, let's mention that those bars are there for a reason and that removing them might not improve your watching experience every time. 

Black Bars on the Sides of the TV Screen

The black bars on the sides of some widescreen TV images (known as “pillarbox”) are among the most common TV aspect ratio problems. They result from the difference between a movie or show's aspect ratio and that on your television. They appear when you watch standard definition 4:3 aspect ratio content, like old movies and TV shows, on a 16:9 widescreen TV.

To get rid of those vertical black bars, you need to zoom in on the image on your remote controller or via TV settings. But zooming might cut off some of the content and make it look distorted.

Black Bars Above and Below the Image

Let’s say the content you’re watching is outputting a 16:9 picture, but the TV has a 4:3 screen. This causes the so-called “letterboxing” effect. Black bars are put above and below the image to center it. 

You can zoom in on the image or adjust your TV's display settings so that it fills the screen. But zooming might cut off some of the content and make the picture look distorted.

This issue can also happen on a 16:9 screen if you watch something filmed in 21:9.

Black Bars Surrounding the Picture

The TV Box outputs a pillarbox and letterbox combo when on HD settings and while using an SD connection (coax cable or composite signal) to connect to the TV. If you are wondering how to fix the aspect ratio on the TV when this happens, you have one of two options:

• Given that black bars appear on one channel, check whether the correct input (HDMI, for example) is used and that the user settings are OK.
• If horizontal and vertical black bars appear on every TV channel, use your remote or TV picture settings to adjust the image. However, note that doing so may cut off parts of the image and make it look distorted.

Check out our TV connection types overview if you wish to learn more about how they work. 

Of course, having the same aspect ratio (TV screen ratio) is always best.  Unless you use the correct aspect ratio (watch a show made in the 16:9 aspect ratio on the 16:9 aspect ratio TV, for example), you'll have to compromise one way or another.

16:9 Is the Industry Standard These Days

16:9 is the standard TV aspect ratio today since most personal computers, TVs, tablets, smartphones, and many other devices can play or record media in this particular aspect ratio. It became a dominant aspect ratio because of the thought that the 16:9 widescreen image best reflects the way our eyes work.

Consequently, the introduction of digital TV and HDTV marked a gradual switch from box to widescreen formats. Although 21:9 is gaining popularity, and many movies are filmed in 21:9 resolutions, the current 16:9 widescreen TV aspect ratio looks to be the industry standard now and in the foreseeable future.

Aspect Ratios That Popular Online Platforms Use

Now, let's see what aspect ratios YouTube, Facebook, and Instagram use. 

YouTube

The standard aspect ratio YouTube uses is 16:9. This means that your video will automatically be changed to 16:9 if you’ve recorded it in a different aspect ratio. YouTube will add white or grey padding (depending on whether you chose the light or dark theme) to fit the video content properly on various devices.

Facebook

If you thought that the standard 16:9 television aspect ratio dominates Facebook, too. Still, this popular platform also uses portrait (4:5) and square (1:1) formats, along with 9:16, to cater to mobile users. 

Instagram

Like Facebook, Instagram uses 1:1, 4:5, 9:16, and 16:9 aspect ratios.

Terms Related to Aspect Ratios

You may have come upon various terms related to aspect ratios, such as native aspect ratio, LCD, and Blu-ray movies. So, let's see what they mean.

• The native aspect ratio is the format in which the content was recorded. Most TVs, monitors, and projectors have settings allowing you to change the aspect ratio, but using the native settings always gives the best performance and lessens the need for aspect ratio troubleshooting down the line.
• Blu-ray is a digital optical disc storage format that has become the industry standard for movies. Most movies filmed today feature a mix of 21:9 or 1.4:1 IMAX. Thus, the image of a Blu-ray movie may go beyond the height of the TV but is cropped to fit the screen. 
• LCD monitors and screens use liquid crystal displays relying on backlights, while AMOLED pixels are sources of light in themselves. If interested, read our LCD vs. AMOLED overview to learn more about their differences. Generally, you’ll find AMOLED on mobile screens only, as the tech is too expensive for big screens. As such, they’ll often have different aspect ratios to TVs and monitors.

Summary

In this article, we defined the aspect ratio and explained the differences between the 4:3 aspect ratio (standard definition) and the high definition ratios. Also, we offered a few solutions if you don't like seeing black bars on your screen. We hope that the article was helpful and that you’ll now have a better understanding of how aspect ratios work.