A reader has a question about fluctuations in Internet speed.

I noticed that the speed changes within Minutes / over time. What might be causing this change? It would matter because sometimes a page might load quickly and other times it may take a little longer. Does it have to do with traffic overall on the Internet? Or is it a local phenomenon?

It’s interesting how you phrased the question. Because there isn’t one big Internet that everyone jumps on at the same time. We all connect to our ISPs who connect us to the servers hosting the sites we want to visit.

Sometimes a site might load slowly because of your Internet connection, but other times the issue could be that the site is just overwhelmed and slow on their end. But just like rush hour traffic, when there’s a bunch of people all on the Internet at the same time, everybody ends up being slowed down by traffic congestion.

Some ISPs have been known to slow down or “throttle” the available speeds of customers. Throttling could be used to alleviate congestion during peak usage, but it can also target specific users the ISP feels are taking up too much bandwidth. Some companies, like Netflix, have paid carriers an additional fee to avoid throttling.

Speed can also be affected by the number of devices using your router. If you’re seeing drastic slowdowns, make sure someone isn’t using your network without your permission.

You should also make sure your the firmware is up-to-date for your router. If a lot of your neighbors are using the same channel for their network as you, consider switching to a less crowded one.

While slight fluctuations are to be expected, if you frequently see drastic ones, it’s time to do some troubleshooting.