Why is 4K called 4K?

[Jerombolo]

Why is 4K called 4K when it only has 3 times as many pixels as HD? FullHD is 1.5 times more pixels and WQHD is 2 times. 4K just sounds wrong to me.

[Vitalius]

Why is 4K called 4K when it only has 3 times as many pixels as HD? FullHD is 1.5 times more pixels and WQHD is 2 times. 4K just sounds wrong to me.

Because there are two ways to describe resolution.

By the Width & the Height, in pixels.

1080p is 1920x1080 where 1920 is the Width & 1080 is the Height. 1080p is also known as 2K because 1920 is the Width and is very close to 2000.

4K is 3840x2160. 3840 is the width and is closest to 4000, so it's called 4K. It'd be called 2160p if it were referred to by it's Height instead.

There's also the fact that 4K is 4 times bigger than 1080p (Full HD), and is called Ultra HD, ultra is Latin for "Beyond" basically.

1080p total pixels = 2,073,600

4K total pixels = 8,294,400

8,294,400 / 2,073,600 = 4

Long story short: The whole naming scheme for resolution is screwed up due to stupid buzz words like "HD, Full HD, WQHD, Ultra HD, etc." and that no one has agreed upon a way to name this stuff.

[thekeemo]

2x length pixels

2x width pixels

2x2 = 4 

HL4 confirmed

[arnavvr]

Why is 4K called 4K when it only has 3 times as many pixels as HD? FullHD is 1.5 times more pixels and WQHD is 2 times. 4K just sounds wrong to me.

 

True 4K is 4096x2160, "UHD" is what it is actually supposed to be called (3840x2160)

[Liam-McShane]

Why is 4K called 4K when it only has 3 times as many pixels as HD? FullHD is 1.5 times more pixels and WQHD is 2 times. 4K just sounds wrong to me.

It has 4x the pixels as 1080p (1K). People call 4K 3840 x 2160.

[Jerombolo]

2x length pixels

2x width pixels

2x2 = 4 

HL4 confirmed

What?

[Lord Sparklebottom]

When 8K becomes mainsteam, "Full Ultra Mega HD"

[thekeemo]

What?

ignore the last line

[Jerombolo]

It has 4x the pixels as 1080p (1K). People call 4K 3840 x 2160.

So they don't count how many in width and length? They count the whole amount?

[Vitalius]

the pixels as 1080p (1K).

Incorrect. Read my post.

@Jerombolo, check my post again.

[Liam-McShane]

So they don't count how many in width and length? They count the whole amount?

yes, 1920 x 1080 = 2073600

 

2073600 x 4 = 8294400

 

3840 x 2160 = 8294400

[Jerombolo]

Incorrect. Read my post.

@Jerombolo, check my post again.

Okay, now I know it, it just confused my that it only has 3 times as many pixels on one line instead of 4 as I thought they'd count it. 

[Jerombolo]

But what does WQHD mean? 

[Jerombolo]

Quad HD?? From where does that come again...

[Megahurt]

Okay, now I know it, it just confused my that it only has 3 times as many pixels on one line instead of 4 as I thought they'd count it. 

Where do you get your 3? 4k is twice the width and twice the height of 1080p. And 1080p (1920x1080) could be considered 2k since it has close to 2000 horizontal pixels.

[Jerombolo]

Where do you get your 3? 4k is twice the width and twice the height of 1080p. And 1080p (1920x1080) could be considered 2k since it has close to 2000 horizontal pixels.

Divide 2160 with 720

[Glenwing]

Divide 2160 with 720

WQHD (2560x1440) is four times 720p (1280x720) or "HD", hence the name "Quad HD".

2560x1440

= (2x1280) x (2x720)

= 2x(1280) x 2x(720)

= 2 x 1280 x 2 x 720

= 2 x 2 x 1280 x 720

= 4 x 1280 x 720

You can do the same thing with 1920x1080 x 4 = 3840x2160.

You can clearly see that 4K is equivalent to four 1080p screens.

However, that's a coincidence, that's not why it's called 4K. 4K means 4,000 if you're familiar with metric shorthand in any way. "4K" is a category of resolutions which are around 4000 pixels horizontally (3840x2160, 4096x2160, etc.)

It is NOT called 4K because it's 4x 1080p. Just look at 8K (7680x4320), it's around 8,000 pixels horizontally and 16x 1080p, not 8x.