Guest Wi-Fi Network Planner

Why your guests slow down your own Wi-Fi

Every device on your home network drinks from the same pipe. Your broadband plan has a fixed amount of download and upload speed, and it is shared across everything connected: your laptop, your partner's video call, the kids' streaming, and every guest who joins the network. One guest starting a 4K stream while you are on an important work call can eat a huge chunk of that shared bandwidth in seconds.

The tricky part is that your router cannot "know" your video call matters more than a guest's movie unless you tell it. Without any limits, traffic is served on a roughly first-come, first-served basis, so bursts from guest devices can starve your own work. This is why routers offer quality-of-service (QoS) and guest network speed limits: they let you draw a clear line between "my" bandwidth and "guest" bandwidth. The Guest Wi-Fi Network Planner exists to help you draw that line at exactly the right number — enough that guests stay happy, with your own work, calls, and streaming protected.

How the planner figures out the right cap

The planner starts with realistic per-guest demand by activity. As a rule of thumb: light browsing and messaging uses about 2 Mbps per guest, video calls need around 6 Mbps, video streaming runs about 8 Mbps, and a heavy mix of streaming plus calls can reach 12 Mbps each. These are comfortable, real-world figures that account for buffering and bursts.

The math then works in three steps. First, it multiplies the number of guests by the per-guest demand of the selected activity to get total guest need. Second, it subtracts the bandwidth you reserve for yourself from your plan's download speed to find what is actually free for guests. Third, it recommends a speed cap equal to 80 percent of that free bandwidth. The 20 percent headroom absorbs brief traffic bursts so your own connection never gets fully squeezed. On the upload side, it estimates guests need roughly 25 percent of their download demand, and compares that against your plan's upload speed so you can see whether uploads are the real bottleneck.

Worked example

Say you have a 100 Mbps download / 20 Mbps upload plan, and eight guests will be streaming at the same time. You decide to protect 25 Mbps for your own calls. Guest need is 8 × 8 = 64 Mbps. After your 25 Mbps, 75 Mbps is free for guests. The recommended cap is 80 percent of 75, which is 60 Mbps — and because 64 Mbps of need fits inside 75 Mbps but outside the 60 Mbps comfort zone, the verdict is "tight but workable": guests fit, but capping them at 60 Mbps keeps a buffer for your own share. On the upload side, guests need about 16 Mbps of your 20 Mbps upload — fine, but clearly uploads deserve a glance if you have many guests.

Practical tips

First, put guests on a separate SSID. Most routers have a "Guest network" toggle in their settings, and it does more than set a name: it also isolates guests from your own devices, so a visitor's laptop cannot see your computers, printers, or smart-home gadgets. Second, set the bandwidth limit under your router's QoS or traffic-control settings — that is where the number this planner recommends actually goes. Third, cap slightly below raw need, since streaming buffers absorb brief dips far better than your work calls do. If you host guests regularly, post the guest network name in a welcome note and rotate the password between guests so old visitors do not stay connected forever. And if the planner's verdict says things are too tight, either upgrade your plan or ask guests to pre-download their shows before they arrive — both beat a ruined video call.