All too often, I find myself trying to help friends, family, and neighbors navigate a complex web of misinformation about their home Internet service and what best fits their needs. Technicians and customer service all too often misspeak regarding technologies and ISPs promote their interest in having your sign up for the "highest speeds" (we'll talk at a high level about why that's in quotes), and for the layperson it can be next to impossible to understand what their options truly are and what will fit them best. Here, I'll try to give a clear answer to some of the most common questions and points of confusion. Let me know in the comments if there are any others you'd like to see answered!

Bandwidth

What is bandwidth?

Bandwidth is what many people are actually referring to when they say "speed". You don't actually purchase different "speeds" when you sign up for a service - speed is relatively constant (electricity moves through a cable or phone line slightly faster than light moves through fiber - no, that's not a typo - but these speeds are so high and fairly consistent that you do not care about them in a residential scenario). Bandwidth is the measure of how much data can be transmitted in a given period of time. If you have a 100 Mbps connection, you can download 100 megabits of data in one second. Note that 100 megabits (Mb) is 12.5 megabytes (MB) which is how you typically see file sizes - one byte (B) consists of 8 bits (b) so there is a large difference between the two. Download bandwidth is how much data reaches your home in a period of time. Upload bandwidth is how much data can be sent out of your home in a period of time.

How much download bandwidth do I actually need?

This varies greatly by your use case. Let's start with the most common residential use case:

Typical Residential User

"I browse the Internet and stream video / conduct Zoom/Teams meetings over the Internet (Netflix/Hulu/SlingTV/etc)"

In this scenario, your largest use of bandwidth is that video streaming. Here's a breakdown of the safe assumptions for needs for download bandwidth for a single video stream:

*Depending on the exact technologies used, this may be less, but this is a guideline to a sure result. More detailed bandwidth requirement information is available here.

Any other common web browsing is going to be fairly minimal compared to this use, so you can fairly comfortably rely on multiplying these numbers by the number of streams of each type likely to occur in your household. For example, maybe you're a family of 4 with one entertainment room TV that's 4k (and streaming 4k, which is still fairly uncommon) and a 1080p bedroom TV, and your two kids might also be watching Youtube on their phones or tablets (we'll assume 1080p, though 720p is common in phones). From the table above, you need:

25 Mbps + 6 Mbps + 2*6Mbps = 49Mbps

Of course, when your kids' friends come over and start trying to stream as well, you might need a little more.

How much upload bandwidth do I actually need?

The good news here is that there are fewer hard and fast requirements here for common residential uses. The bad news is that this means it's largely up to your discretion. This is also why many types of residential Internet access - including cable, DSL, and even some fiber technologies - are technically incapable of delivering symmetric bandwidth (where you have the same upload bandwidth as download bandwidth). It is why we see common offers like 100 Mbps download with 5 Mbps upload.

Let's discuss the household use cases for upload bandwidth:

• Normal Browsing: Yes, just browsing the Internet, sending and receiving emails, watching Netflix, etc all require upload bandwidth. Usually, these activities do not require much bandwidth, but they do require some. Your largest use of upload bandwidth is probably uploading videos of your pet to social media. 5 Mbps is probably just fine for a family of 8 doing just these things.
• Backups: Hopefully, you are backing up your data somewhere, and likely, that is to a cloud service like iCloud, BackBlaze, or Carbonite. These backups occur either on a set schedule or when the computer is unused and powered on for a while. You can adjust these settings to your needs. If you want to keep a lower amount of upload bandwidth, you can cap the amount that these are allowed to use in their settings.
• Online Gaming: Believe it or not, online gaming doesn't require significant upload bandwidth. You're still in the Normal Browsing category. Unless you are streaming your games. ☟
• Streaming or Video Conferencing: This requires sustained upload bandwidth. When discussing download bandwidth, we talked about bandwidths required for various stream qualities - the same apply here, but in reverse. Chances are, if you're streaming your webcam to a video conference, you're doing so at 720p, so you only require up to 3 Mbps for that stream. If you're streaming a video game to Twitch or Youtube (or your children are), that may be 1080p (which requires 6 Mbps). Much of this will quickly put you over that default 5 Mbps upload bandwidth available with many cable plans.
• Publishing video or other large content: This doesn't require a specific amount of upload bandwidth, but since you're going to be using as much bandwidth as you have available for a period of time, your upload bandwidth will significantly affect the time it takes to upload your video or other file. If you're doing a lot of this, it is worth it to ensure you have higher upload bandwidth for your productivity.

Single-stream vs Multi-stream

One final note on bandwidth - and this applies to both upload and download - don't expect that because you have a 1 Gbps connection that you'll ever see a single transfer running at 1 Gbps. A single stream takes a single path through the Internet, which may not deliver that full bandwidth (and the remote end sending you data may not be capable or willing to send you data that quickly). When you purchase a 1 Gbps Internet connection, you are purchasing the ability to use up to 1 Gbps at a time across many streams, meaning if you have 10 different computers downloading from 10 different websites, it is reasonable to expect that all 10 of them should be able to achieve close to 100 Mbps.

Also, note overhead: 100 Mbps of throughput does not mean that you will be able to transfer 100 Mb of a file in one second; it means you'll be able to receive 100 Mbps of traffic in one second. There is overhead involved which varies depending upon the application.

Roadmap

I wanted to get this out and available as quickly as I could, so there'll be more examples and answers to come. Some of the items I'd like to address are:

• Latency
• Troubleshooting perceived "slow speeds"
• Cable vs Fiber vs DSL vs Wireless
• Renting vs buying your router and access points
• QoS

If you're looking for any in particular, please drop a comment below. I'll try to answer the most common questions first.