The question is not whether max speed is the same for more people, which it obviously is not. What I don't know if the number of devices alone, even when idle, kills your bandwith.

I've noticed our office Wi-Fi is rather slow and the explanation from IT is that there are so many smartphones etc. However most of the time most of them are not actually downloading anything. All the computers are using wired ethernet. Access points are properly managed with non-conflicting bands as far as I can tell.

So will you get worse downloads with access points supporting 20 devices as opposed to 2 even if the other connected devices are not doing anything? Does it depend on the tech ie 802.11 g/n/ac?

I tried searching, failed. And to be clear, this is not about a real network problem but more of a “how things work” type of question. In this case, very specifically about the number of passive—yet still connected— devices present degrading the performance of any active device(s).

2 Answers 2


I spoke with a person who actually designs Wi-Fi hardware on low level signal processing et al.

The simple answer is: "No, the number of devices connected to an AP have little to no effect if they're not doing anything".

Longer answer gets a bit involved but basically Wi-Fi physical layer is entirely asynchronous technology and the clients do not "say" anything much "often" unless they want something. Obviously "often" is in machine terms, to put things into perspective the client Wi-Fi chip has only about 76us to react during a transaction so almost all of the low level functionality is handled in dedicated hardware even for host-based solutions. But very little real overhead is created by idle clients.

Wrt several devices taxing the network, it is more pronounced in a near-far case where the clients cannot "hear" each other. In this case they can both (or several of them) access the AP at the same time causing stalls and resynchronization, not very different from old-school coaxial ethernet collision issues. But if you have a room full of guys with their Android phones connected to the same AP, they can "hear" the band is in use and wait for their turn.

  • Yes but having more devices on wireless can increase interference that reduces the range thus reduces the connection speed that can be negotiated. I tested this by reconnecting all devices to 5ghz and i watched my 2.4ghz band increase steadily by 5db to the test device i had stationed. I needed to free up my 2.4ghz band for some legacy devices with poor range. Doing that worked. Prior 6 months and the baby monitor was lagging. Now it has been working fine for 4 months.
    – ldrrp
    Oct 4, 2019 at 14:10
  • @ldrrp - a device can't "increase interference" unless it DOES something with WiFi. If that weren't a true statement, all mobile devices would drain their battery quickly; wifi transmission is a significant use of battery power. Those devices must have been making some background use of wifi. To make sure a test is valid, its essential to turn off all apps background ability. Or just turn on "low battery mode" on all devices - that should reduce activity to a minimum when screen is off. Jan 28 at 19:07

This is a broad topic and dependent on the network equipment and devices connected. In most cases, WiFi is not its own Internet connection, it shares an Internet connection with the entire network.

Theoretically, just having devices connected to WiFi does not slow the speed. But the more devices connected and doing something, the bandwidth has to be shared, thus affecting the speed.

The phone may look idle, but they are not always as it appears. Even idle smartphones are often using the WiFi in the background to update/sync all the apps that are running. Especially those with settings to only do certain tasks when connected to WiFi, like Apple's cloud backup.

This article discusses the other performance issues of WiFi radio interference causing issues.

Additional data about running background applications - What is Eating Up Battery Life On My SmartPhone: A Case Study.

  • Wired WAN access is more than an order of magnitude faster so the bottleneck is not there. So according to what you're saying having n devices connected won't kill the wifi bandwith as long as they're idle? Does this also apply to the venerable 802.11g? I know that does not have a lot of bandwith to toss around to start with.
    – Barleyman
    Apr 29, 2016 at 13:54
  • 2
    No. What I am saying is, what appear to be idle devices may be using bandwidth in the background. There really is no way for us to give you a definitive answer for the reasons I outlined in my answer.
    – CharlieRB
    Apr 29, 2016 at 14:08
  • 1
    No reason to get upset. There are just too many factors involved for us to be able to solve it for you. Each network is unique and has its own set of issues. There is no quick easy answer to give you.
    – CharlieRB
    Apr 29, 2016 at 14:25
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    Sorry. I thought this was an actual problem. This is why I have responded the way I have; site guidelines state "You should only ask practical, answerable questions based on actual problems that you face. Chatty, open-ended questions diminish the usefulness of our site and push other questions off the front page." Not trying to be a jerk, but this site just isn't suited for theoretical/hypothetical/curiosity type questions.
    – CharlieRB
    Apr 29, 2016 at 15:25
  • 1
    @Barleyman This is really simple. Read the guidelines in the help center. If you do not like or agree, then do not use this free site. No one is forcing you to use this site. Although, if you choose to use it correctly, it might be useful for you.
    – CharlieRB
    May 3, 2016 at 13:28

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