Any of guys know how big 4K files get? I know it's impossible to directly say what it would be. But you can always estimate, I say, that 8 minutes of 1080p would be around 100MB. Could any of you estimate size of such file?

My guess is that 4k files would be around 4*1024 bytes.

Seriously though, the size of 8 minutes of 1080p could vary greatly depending on the bitrate, frequency of keyframes, motion, etc. A video with low motion should have higher compression. A video with lots of motion or frequent scene changes would have a much lower compression. The same variability would occur no matter what the resolution.

4x1024 bytes = 4KiB, you realize that?

The KiB notation dates from '98, long after we were taught...

"You'll have to forgive me. I'm Old." - Phil Fish (Abe Vigoda on Barney Miller)

I still don't get what you meant by 4*1024. You don't need excuse yourself, I need to excuse myself for not having enough knowledge to comprehend your answer.

developed from binary coding,
representation of kilo anything,
2*2*2*2*2*2*2*2*2*2 = 1024
4 kilobyte 4*1024

slack definition of kilo, 1000,

1, marketers add 2.5% to the size of anything, and say they are bigger than the competition,

2, why so many terabyte drives, don't hold a terabyte; even before formatting

3, because the practitioner is stupid, lazy, or both.

That still doesn't explain it, I knew this already.

Reverend Jim thought that you were talking about 4K as in 4 kilobytes (or 4KB), and by that measure, the size of a 4KB file is, well, 4 * 1024 bytes. He simply did not realize you were talking about that new ultra-high-definition format for video and televisions that is commonly called "4K", which refers to the fact that it has 4 times the resolution of 1080p video.

Since 4K is 4 times more pixels than 1080p, then a rough approximation of the file sizes will be 4 times that of an equivalent 1080p video file. But, of course, most video compression methods aim to achieve as much compression as possible without negatively affecting the quality of the picture, i.e., it merges frames or parts of the frames that are static of several video frames (e.g., a static background), and also compresses groups of pixels that have nearly identical color values (e.g., making bigger pixels). So, when the resolution is as high as 4K, there is probably a lot more opportunity for compression too, i.e., when the resolution is higher quality than what you can perceive with your naked eyes, it can compress a lot before you notice any difference. So, I would say that it might not be as much as 4 times the size of 1080p video, maybe as low as 2 times bigger, or even less, depending on the encoding quality settings.

Oh! Well, it's my fault actually, I could've mentioned 4K-UHD or something like that.

You have to leave at least 2 options, so people can always choose the wrong one

blame people who don't know that K means Kilo to invent something meaning something else that causes confusion when used outside of its intended context...

I looked at the question, albeit not closely enough as it turns out, and assumed the OP must have meant KB. To be honest, Kilo never entered my mind in the context of the post title - but I do know what you mean, and agree 101%.

Reverend Jim thought that you were talking about 4K as in 4 kilobytes

Actually, I knew what he was talking about. I was just attempting to be funny (fail). That's why the next sentence started with "seriously".

Depends what you're talking about (again). Unfortunately there are two meanings for "4K".

One is the industry standard, 4096x2160 and the other is UHDTV which is 3840x2160. I will continue to assume 4K means 3840x2160 as this is what monitors and TV broadcasts will be.

Assuming that you're watching on a standard TV at 24fps a 10bpp RAW, video only, 4K video will consume ~79.1MB/frame or ~1898.44MB/sec.

H.264 can achieve a compression ratio of approximately 64% (ref)

For the purpose of mathematics, we will assume that this is the average of all frames and therefore, that every frame produces the same compression ratio.
This means that with HEVC, 4K will consume approximately 683.44MB/sec

Hope this helps.

EDIT: This calculated ratio is somewhat better than the first movie available in 4K which was 160GB for 129seconds