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TV Aspect Ratio: Understanding Widescreen, 16:9 and 4:3

old style 4:3 TV in an empty room

You hear plenty about widescreen TV these days, but what does it mean exactly? Discover the difference between 4:3 and 16:9 in this guide to TV aspect ratios.

The TV aspect ratio is a term you often hear when discussing a television or projector screen.

You might hear about ‘widescreen’ and ‘4 by 3’, but what does it all mean exactly?

Well, it can be one of the factors to consider when looking to buy a new television or projector screen – and it’s another part of the seemingly endless stream of technical jargon that can confuse you.

You don’t understand it, and the person trying to sell you that new TV doesn’t seem to understand it either.

The thing is, you don’t really need to understand most of this stuff.

Much of it is just fancy terms and numbers to make that expensive new purchase of yours sound more exciting!

However, learning some jargon can improve your understanding of the technology – and sometimes help you get the best from it.

So what’s the aspect ratio of your television all about?

What Is the Aspect Ratio of Your TV Screen?

The aspect ratio refers to a TV screen’s shape – or how wide it is compared to the height.

You may also come across this term when buying a projector screen.

It is a similar concept to the aspect ratio of a movie – however, this article is about the shape of your screen – rather than the video image showing on that screen.

The aspect ratio is calculated by dividing the width by the height.

So if you know the aspect ratio of a TV screen, you will know its shape.

What Is a 4:3 Aspect Ratio?

For those old enough to remember, the traditional shape of a television screen was almost square.

It was slightly wider than it was high, but not by much, and matched the shape of the picture sent to your TV.

This was known as a ‘4 by 3’ screen, but you may also see this written as 4:3 or 4×3.

This means that the screen was 4 units wide and 3 units high.

4:3 TV Aspect Ratio Diagram
4:3 TV aspect ratio

The physical size of the units doesn’t matter – it could be 4 inches by 3 inches, 4 feet by 3 feet or 8 feet by 6 feet.

But, the relationship between the width and the height is always 4 across and 3 down.

Because the screen’s actual size doesn’t matter, it is often easier to express this 4:3 relationship as a ratio.

So, if you divide the width by the height:

4 ÷ 3 = 1.33

So, 1.33 – or 1.33:1 – is the aspect ratio of a 4:3 TV or projector screen.

You may see the aspect ratio written as either of these numbers, but they mean the same thing.

When you see these terms, it tells you the basic shape of that screen.

What Is a 16:9 Widescreen Aspect Ratio?

As with all technology, times changed, and the boffins tried to improve existing TV technology.

While the aspect ratio of movies was also originally 1.33:1, this changed while the shape of a TV screen stayed as a ‘square.’

You would see a much broader screen in a movie theater – more like a rectangle than a square.

This wide image shape was thought to more closely reflect the way that eyes worked – and so was a more natural way to see things.

So, with the introduction of HDTV and digital television, the result has been a slow but steady switch to ‘widescreen’ televisions.

These days, all new OLED and LED TVs are now widescreen.

16:9 Widescreen TV Aspect Ratio
16:9 widescreen TV aspect ratio

The widescreen image you see on your TV isn’t quite the same shape as they use in movies, but it is similar.

The standard HD aspect ratio is ’16 by 9.’

As with a 4:3 image, this means the picture is 16 units wide and 9 units high – so much wider in comparison to the height.

You’re probably way ahead now, but this widescreen image can also be expressed as a ratio.

Like this:

16 ÷ 9 = 1.7777

This number is usually rounded up to 1.78 – so when you see reference to 1.78 or 1.78:1, you know that the image or TV screen will be widescreen.

This is also known as 16:9 and 16×9.

If you want to know more, learn how to calculate the dimensions of your screen using your TV’s aspect ratio.


So now you’ve learned a thing or two about the TV aspect ratio, you can feel more confident about another piece of jargon that you will come across.

All new televisions and computer screens are now produced with a widescreen aspect ratio, so it is good to know a little background about it.

You won’t see many old 4×3 TVs these days, but 1.33 computer monitors and projector screens are still around.

Have you ever wondered why you get those black bars on your screen when you play a movie on your DVD or Blu-ray player?

Well, now you understand the aspect ratios of TV screens, you are also in an excellent place to figure out why.

You can find more about this in the article on the aspect ratio of DVD and Blu-ray movies.

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Understanding TV Aspect Ratios
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About The Author

Paul started the Home Cinema Guide to help less-experienced users get the most out of today's audio-visual technology. He has been a sound, lighting and audio-visual engineer for around 20 years. At home, he has spent more time than is probably healthy installing, configuring, testing, de-rigging, fixing, tweaking, re-installing again (and sometimes using) various pieces of hi-fi and home cinema equipment. You can find out more here.

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