4K and 8K Ultra HD resolutions are both high-definition video formats, but they differ in the number of pixels they display. 4K has approximately 3840 x 2160 pixels, while 8K has double the pixels of 4K Ultra HD with a resolution of 7680 x 4320 pixels. This means that 8K images are significantly sharper, clearer, and have more detail than 4K images.