Before I can explain the difference between UHD and 8K, please let me clarify what they are.
UHD and and 8K refer to a technical term called 'resolution'. Computers, Tvs and pretty much every display device has a resolution.
And the resolution refers to how many pixels are in that display.
So, they are both resolution but... Is UHD the same as 8K?
Is UHD the same as 8K?
The short answer is no but there is a caveat.
UHD is a resolution that contains 3840 pixels (wide) and 2160 pixels (height). Sometimes it is also called 'Ultra HD' or 4K.
8K is becoming a common resolution, it contains 7680 pixels (wide) and 4320 pixels (height). Sometimes it is also called 'Ultra HD' or UHD2.
So depending on who is talking, 8K and UHD may mean the same thing (synonyms).
8k literally means eight thousand.
Total number of pixels
UHD: 8294400 pixels. (More than 8 million pixels)
8K: 33177600 pixels. (More than 33 million pixels)
Comparing vertical pixels
8K has 4320 vertical pixels and UHD has 2160 pixels. So UHD has less vertical pixels than 8K.
Comparing horizontal pixels
8K has 7680 horizontal pixels and UHD has 3840. Thus UHD has less horizontal pixels than 8K.
Which is better UHD or 8K?
Technically speaking, 8K is always better. A 8K screen has four times the number of pixels than that of a 8K screen. That’s why 8K has higher image quality than UHD.
But it may not be the best for your budget.
Note: To get the full benefits of a 8K TV you need to have 8K content.
I've compiled a few examples to help you understand the difference.
Security camera example
Tip: Turn on the caption button if you need it. Choose “automatic translation” in the settings button, if you are not familiar to the english language. You may need to click on the language of the video first before your favorite language becomes available for translation.