Do you know how fast your Internet connection is? What is the unit used for measuring Internet connection speeds? How fast does your Internet connection need to be if you want to stream a movie from Netflix or a similar service?

I think everybody should be able to answer these questions. It’s part of being Internet-literate. You know how fast your car is traveling when you use it and you know that car speed is commonly measured in miles per hour (or kilometers per hour if you live outside the US). Before you read the rest of this Tech Tip please go measure your current Internet connection speed using the SpeedTest web site. Now that you know the speed of your Internet connection, we can put it in context.

Let’s start with some terminology. Internet speeds are most commonly measured in bits per second (bps). All data (email messages, pictures, etc) are made of small chunks of data named bits, thus bits per second is a useful measure. Pictures are often megabytes in size and movies are gigabytes in size. (Read my previous Tech Tip if you’d like a refresher on bits, bytes and kilobytes.) These days speeds are written in kilobits per second (Kbps) or, increasingly, megabits per second (Mbps).

In the mid-1990s, people commonly used dial-up modems to connect to the Internet via their telephone line. The fastest modems could offer a 56 Kbps connection. When broadband Internet connections, like DSL were introduced in Seattle in the late 90s, a common speed was 256 Kbps. In 2014, introductory DSL speeds are commonly 1500 Kbps, which can alternatively be written as 1.5 Mbps. When I tested my connection’s speed, the downstream or incoming speed was 28.4 Mbps, which could be written as 28,400 Kbps. That’s about 500 times faster than a 56Kbps modem! The upstream or outgoing speed of my Internet connection was 6.1 Mbps.

It’s common for Internet connections to be asymmetrical. This means that the incoming speed is faster than the outgoing speed. This is reasonable, in most situations, since we tend to receive, or consume, more data than we send.

Above I mentioned that my speeds were 28.4 Mpbs and 6.1 Mbps. In shorthand these speeds might be written as 28.4/6.1. The downstream speed is typically faster and is written first. Then the slower, upstream speed is listed second. This is useful to know since Internet provides like Comcast and CenturyLink often list the speeds in their ads or on your monthly bill. Look at your next Internet bill to see if your Internet provider lists the speeds they are providing to you. Compare those speeds with the results of the test you conducted yourself.

Since speeds can fluctuate for a number of reasons, test your Internet connection speed a few times to see how it varies and develop a baseline for what is normal for you. If your speed is consistently less than what you’re paying for, contact your Internet service provider, as there may be something wrong. I think everybody should know their average Internet connection speeds. By knowing what’s normal, you can quickly see if your Internet connection speed is causing the slowdown you’re experiencing.

Now that you have a brief history of Internet connection speeds and their units of measure, let’s talk about how fast of a connection you need. The speed you need depends upon what you’re doing on the Internet and how many people are concurrently using your Internet connection. Here are some general guidelines:

For the average household of two or three people, I think the slowest connection that’s reasonable for viewing web sites, watching the occasional video clip and sending and receiving email is around 3-5 Mbps. If you want to stream video from Netflix or a similar service, then a connection speed of video. Netflix provides specific recommendations for streaming video including: 3 Mbps should for standard definition (SD) video, 5 Mbps for high definition (HD) video and 25 Mbps for ultra high definition (4K) video. For small offices with a handful of employees, I commonly recommend an Internet connection of at least around10 Mbps and sometimes faster connections depending upon their needs.

If you’d like to estimate how long it would take to transfer a certain amount of data using a network connection of a known speed you can use the CalcTool web site to easily calculate the time.