UNDERSTANDING BANDWIDTH

If you’ve ever tried to drink a milkshake through a straw, you understand bandwidth. Drinking a soda through a straw is simple. Soda is just water with bubbles. It’s not thick, and you don’t need to apply much suction to quench your thirst. But try to drink a thick milkshake through that same straw and you might have problems. Either you have to suck much harder or you need a bigger straw.

The data we transmit on the internet is like that. Some things, like a simple email text message, require very little bandwidth because there’s not much data. But a 4K video stream requires a lot of bandwidth because the data files are so large.

Sure, you could theoretically watch a 4K video stream with any bandwidth capacity (even dial-up), but you’d have to download the entire file first, which could take days. If you want to just click and watch, the internet pipe needs to be wide enough to accommodate all that data.

THESE DAYS, IT’S ALL ABOUT THE VIDEO

So let’s jump into the specifics. In our new pandemic-driven normal, it’s all about the video. Emails and basic web surfing consume a relatively small amount of bandwidth. Photos and music consume more, as do games. But it’s video that’s the big bandwidth hog. So that’s what we’re going to look at in this guide.

Bandwidth is generally measured in megabits per second, written as Mbps (with a lower-case “b”). That’s millions of bits per second. As you can see in the following chart, Netflix says the absolute minimum bandwidth it needs is 0.5Mbps. That will be for heavily buffered, very low resolution video.

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By contrast, to watch a movie streamed in glorious 4K, your connection will need 20Mbps. That means your pipe needs to be able to send 20 million bits in one second. As you can see, different levels of resolution require different amounts of bandwidth.

Fortunately, Netflix and YouTube (and most other streaming services) either let you specify the quality of video you’re watching (and, by extension, the bandwidth you use) or automatically throttle your video based on your existing bandwidth.

In a world where you’re probably only watching one Netflix stream and possibly a YouTube video at a time, this works fine. But when you and your spouse and your kids must all be online at once, all using video, the requirements change.