The tool below works out whether the slowdown is your modem, your WiFi, your plan, or your ISP's network — and tells you exactly what to do next. Run a speed test at fast.com first, then use the tool.
The most common causes are an old modem with a 100Mbps WAN port that limits faster plans, WiFi interference, network congestion at peak hours, or a speed plan that no longer suits your household. Run a speed test at fast.com and compare it to your plan speed to identify the cause.
If ethernet is fast but WiFi is slow, the problem is wireless — not your NBN connection. Try switching to the 5GHz band, move closer to the modem, or consider a WiFi 6 modem or mesh system.
Yes. Modems made before 2020 often have 100Mbps WAN ports — meaning even a 250Mbps plan caps at 100Mbps. If your modem is over 3–4 years old and speeds are consistently below your plan, a new modem is usually the fix.
Slow speeds between 6–10pm are almost always network congestion — your ISP doesn't have enough capacity at peak time. This is an ISP infrastructure issue, not something you can fix at home.