Why your internet is slow, and how to prove it

Work through these in order. The list is sorted by how often each one turns out to be the answer, and the first three cover the large majority of cases.

1. Test properly first

Everything below depends on measuring the right thing.

1. Plug a laptop into the router with an Ethernet cable.
2. Stop anything else using the connection — streams, downloads, game updates.
3. Run a test at fast.com and at speedtest.net, to a nearby server.

If Ethernet gives you roughly the speed you pay for, your line is fine and the problem is WiFi. Skip to step 3. If Ethernet is also slow, keep going.

2. Restart the equipment, properly

Unplug the modem or ONT and the router from power. Wait sixty full seconds — this matters, capacitors hold state. Plug the modem back in first, wait for its lights to settle, then the router.

This fixes a genuinely surprising share of problems: a wedged DHCP lease, an overheated modem, a firmware update that half-applied.

3. WiFi is almost always the real answer

If Ethernet is fast and WiFi is not, nothing about your plan will help.

• Distance and walls. 5 GHz is fast and short-range; 2.4 GHz reaches further and is slower. Brick, concrete, tile, metal and mirrors all block signal hard.
• Router placement. Central, elevated, out in the open. Not in a cabinet, not on the floor, not behind the TV, not next to the microwave.
• Channel congestion. In an apartment building you are competing with thirty other networks. Most modern routers pick channels automatically; older ones do not.
• Your device. A phone from 2018 has a WiFi radio that cannot exceed a few hundred Mbps regardless of the plan.

4. Something in the house is eating the connection

Check for: a game console downloading a 100 GB update in rest mode, cloud backup running its first full sync, a security camera uploading 4K continuously, or a computer applying system updates.

Most routers have a traffic page showing which device is consuming what. Look there before blaming the provider.

5. You hit a data cap

Many cable providers cap at 1–1.25 TB per month and throttle hard after it. If the slowdown started abruptly in the third week of the month and clears on the first, this is it. Check the usage meter in your provider's app.

6. Peak-hour congestion

If speeds are fine at 10am and collapse at 9pm, your street is oversubscribed. This is a cable characteristic. Test at several times of day and write down the numbers — a pattern is what gets a technician sent out.

7. It really is the line

Once you have ruled out the above, you have a case. Before calling, collect:

• Speed test results over Ethernet, at three different times of day
• Screenshots showing the number against what you pay for
• Any modem event log entries (in the modem admin page, often 192.168.100.1)

Then ask specifically for a line quality check and, if the numbers stay bad, a technician visit. Ask for a credit for the affected period — most providers will give one if you ask plainly and have the numbers.

When to just upgrade

If Ethernet consistently delivers your full plan speed and it still is not enough for what the household does, then the plan is genuinely too small. That is the only case where paying more actually fixes anything.