A 4K Blu-ray player will work on a regular TV, but it's important to consider other factors beyond resolution. A budget 4K Blu-ray player will give you 4K Blu-ray disc playback, but it's important to consider factors such as HDR support, upscaling, audio quality, connectivity, and built-in smart features. If you have a 1080p TV, a 4K Blu-ray player will downconvert the 3840 x 2160 resolution video on the disc to a 1080p format your TV can display. It will also bypass any high dynamic range (HDR) metadata since regular HDTVs aren't capable of processing that information.
If you want to get the most out of your 4K Blu-ray player, it's worth investing in a 4K TV. 4K Blu-rays have four times the picture resolution of regular Blu-ray's 1080p HD video and support high dynamic range, which provides a greatly expanded color spectrum. Additionally, some standard Blu-ray discs can look much smoother when upscaled for a 4K screen, but you shouldn't expect full 4K quality. To enjoy 4K Blu-ray, you'll need an HDMI cable that supports HDMI v2.0. Ultimately, a 4K Ultra HD Blu-ray player is the way to go if you have or plan to buy a 4K UHD TV, as they offer the best picture quality you can get today with 4K 3840x2160 resolution.