As you’d expect, TVs know what resolution they’re displaying. But they generally won’t tell you. Most TVs don’t have an option to check whether you’re watching something in 4K, 1080p, or any other resolution. You’ll need to understand what content is available instead.

Why You Can’t Tell the Difference Between 4K and HD

There are several reasons why your new 4K TV may look identical to your old HD TV. The issue may be that your source video isn’t actually in 4K, but before we get into that, let’s knock out some of the more typical reasons why your 4K TV looks just like an HD TV:

Your TV Is Small: Resolution is determined by the number of pixels in an image. As screens get larger, the space between those pixels increases, which can decrease the visual quality of an image. That said, 1080p starts looking “bad” at around 60″, and that’s where you can really see the difference between 4K and HD. Your TV Needs Calibration: Like a computer monitor, your TV needs to be calibrated for color, brightness, and contrast. This is usually done by the manufacturer, but if you’re disappointed by the quality of your TV, then it probably needs to be calibrated. Additionally, you should turn off any motion smoothing on your TV. Your TV Is Cheap: Not to be rude or condescending, but cheap TVs can look like crap. If a 4K TV is made from cheap components, then it may not look any better than an HD TV. Plus, some cheap 4K TVs aren’t UHD TVs, which means that they lack modern contrast and coloring technologies. (UHD is the TV equivalent of Apple’s Retina display). You’re Using RCA Cables: Don’t use the colored jacks behind your TV, use an HDMI cable. RCA cables have been around since the ’50s, and while newer component RCA cables are capable of transmitting high-resolution video signals, they’re almost always capped at 1080p. It’s Just You: All humans are capable of seeing the difference between 4K and 1080p. 4K is four times the resolution of 1080p, after all. But if your expectations are too high, the difference may seem negligible to you.

If your 4K TV still looks bad despite its size, price tag, and proper calibration, then the issue probably lies with your source video.

Upscaling can help make 1080p content look better on a 4K TV. But upscaling isn’t magic, and you’ll get the best picture with native 4K content.

Cable Doesn’t Support 4K Yet

For whatever reason, you can’t get cable in 4K. The high-resolution format has been around for a long time, but it’s generally useless if you’re just watching cable TV. Some set-top boxes support 4K streaming and video downloads, but don’t let the cable company fool you, cable TV maxes out at 1080p.

In some cases, cable looks different (not objectively better or worse) on 4K TVs. This is the byproduct of better, brighter, and clearer lighting technologies; it has nothing to do with the higher resolution.

Are You Actually Streaming in 4K?

If you’re streaming on your PC, there are some additional limitations. Netflix requires specific hardware and software for 4K streaming on a PC, for example.

Alongside the lack of actual 4K content on streaming services, the internet’s limitations make 4K streaming a little funky. For one, all stream-able 4K content is compressed like hell to reduce file size. While Blu-Ray discs transfer 4K content at around 80 Mbps, streaming platforms like Netflix compress their content to the point that it can seamlessly transfer at about 25 Mbps. The consequence of this compression, as you’ve probably guessed, is that stream-able 4K content looks worse than the 4K video that you’ll get off a Blu-Ray disc.

That said, you can’t stream 4K content unless your internet speeds are somewhere around 25 Mbps. If you don’t know your internet speeds, take the Ookla speed test.

Are You Watching DVDs or Blu-Ray Discs?

This is probably obvious to some people, but DVDs can’t carry 4K video. In fact, the max resolution of DVDs is 480p, which isn’t even 720p! If you want to get the most out of your 4K TV, it may be time to upgrade to Blu-Ray.

But there are some restraints to Blu-Ray. Old movies, even if they’ve been remastered for Blu-Ray Ultra HD, aren’t necessarily in 4K. Movies that were shot on analog film (Alien, Rocky) usually have an extremely high resolution and are actually downscaled for 4K releases, but movies shot during the early age of digital cameras (Star Wars Episode II, for example) are rarely available at resolutions higher than 1080p.

Not All Video Games Are 4K

As of right now, the only game consoles that support 4K gaming are the Xbox One S, the Xbox One X, and Sony’s PlayStation 4 Pro. The original Xbox One doesn’t offer 4K, and the original and slim PS4 (while it can play 4K videos and Blu-Ray discs) doesn’t support 4K gaming). Contrary to logic and reason, the Nintendo Switch is a 1080p console, and it runs some games at 900p while attached to a TV (if it looks terrible on your 4K TV, adjust the sharpness and contrast).

Throughout this article, you’ve probably noticed a trend. Streaming services offer 4K, but their libraries are full of 1080p movies. Blu-Ray players are 4K machines, but not all movies are actually in 4K. The same goes for console games. If you want to check whether or not your favorite games are actually in 4K, check the Xbox One 4K guide from Windows Central or the PS4 4K list from Digital Trends.

If you’re playing a 4K ready game, but it still looks like crap on your TV, then it’s time to dive into your console’s menu. For the Xbox One, you’ll want to press the Xbox button, go to “Settings,” open “Video Options,” and turn on all of the HDR and 4K options. For the PS4, go to the home screen, open the “Sound and Screen” menu, and adjust your resolution in the “Video Output Settings.”

Some TV Apps Might Tell You When You’re Watching 4K

While TVs don’t generally display this information in their own interfaces, some streaming apps might tell you. Of course, this is only useful for that individual application.

The YouTube TV app, for example, has a handy “Stats for Nerds” option that displays your current resolution, connection speed, and other geeky info.

Open a video, select the three dots, and open the “Stats for Nerds” option (the bug icon). Then, an overlay will give you your current video resolution. Go back to this open when you’re ready to hide the overlay.

Alongside the video’s current resolution is an optimal resolution. The optimal resolution is calculated based on your screen’s actual resolution, and it should be identical to your current resolution. If your current resolution doesn’t match the optimal resolution, then check your connection speed. If the optimal resolution for a video isn’t 4K on your 4K TV, then the video itself isn’t in 4K. (Keep in mind that 4K is technically 3,840 x 2,160. People “4K” keep things simple).