"The internet is slow" describes two completely different problems. Either the connection coming into your house is slow, which is between you and your provider, or the connection is fine and your Wi-Fi is failing to deliver it around the house, which is fixable on your side of the wall.
People spend real money solving the wrong one. They call the provider about a Wi-Fi problem, or buy Wi-Fi gear to fix a provider problem. Ten minutes of testing tells you which fight you're actually in.
Minute 0 to 3: test at the source, wired
The only measurement that isolates your provider is a wired test as close to the modem as possible. Take a laptop with an Ethernet port (or a USB Ethernet adapter, worth the $20 to $40 to own one), plug it directly into your router, and run a speed test. If you can plug into the modem itself even better, though some setups make that awkward.
Compare the result to the plan you pay for. Wired, you should see something close to the advertised number. Two outcomes:
If the wired result is far below your plan, stop. Your problem is upstream: the modem, the line into the house, or the plan itself. No router, mesh kit or access point will change this number. That's a call to your provider, armed with your wired test result, which they cannot wave away as "Wi-Fi interference."
If the wired result matches your plan, your internet is fine. Everything slow from here on is Wi-Fi, and it's yours to fix.
No laptop with Ethernet? Run the speed test on your phone standing one metre from the router. It's not as clean, but a good result there still shifts suspicion onto coverage.
Minute 3 to 6: speed versus signal, room by room
Now walk to wherever things feel slow and run the same speed test on your phone. Watch two things: the speed result and the Wi-Fi signal bars.
Full bars but slow speed suggests congestion or an overloaded router rather than distance. One or two bars and slow speed is a coverage problem: the signal is simply too weak by the time it reaches that room, and speed decays with signal. That's the classic far-bedroom situation, and it's the one people mistakenly try to fix with a bigger router. We've written before about why a new router rarely fixes this; weak signal in far rooms is a placement and coverage issue, solved by putting an access point closer to where you sit.
Note the pattern as you walk. Slow everywhere, even beside the router, points back upstream. Fast near the router and slow far away is coverage, full stop.
Minute 6 to 9: one device, or all of them?
Next question: is it one device or the whole house?
If everyone's devices struggle at the same time, in the same places, the network is the problem. But if one laptop crawls while a phone beside it flies, the network is innocent. Old laptops with dated Wi-Fi radios, a stale driver, a VPN that routes everything through a far-off server, or a machine quietly running updates will all produce "slow internet" on one device only.
The quick test is to put two devices side by side and run the same speed test on both. Thirty seconds, and it either convicts the device or clears it.
Timing matters too. Slow only in the evening, when the household (and the neighbourhood) is streaming, hints at congestion: either your plan is undersized for the household or your router is buckling under the device count. Slow at all hours points at coverage or the line.
Minute 9 to 10: read your verdict
You now know which of three problems you have:
Wired test slow: provider problem. Call them with your numbers.
Wired test fine, weak signal in far rooms: coverage problem. The fix is access points or a well-placed mesh unit, not a plan upgrade.
Wired test fine, strong signal, still slow on all devices at busy times: capacity problem. Look at the router's age and the plan tier.
Most "slow internet" service calls we take resolve into the second category, and the household has usually already paid for a speed boost that changed nothing.
If your ten minutes produced a coverage verdict and you want it fixed properly, a Wi-Fi site survey and heat map turns the guesswork into a floor plan with answers on it. And if the testing itself is the unappealing part, get in touch and we'll run the whole diagnosis for you.
Cabling, networks, cameras, access control, smart homes, hosting and software for homes and small business across Southwestern Ontario. Twenty-plus years in the trade, and we still answer the phone.