Why Your Internet Is Slow and How to Fix It
Your internet doesn't have to feel like it's on vacation. Here is the full diagnostic checklist network engineers actually use.
1. Start with a baseline speed test
Before chasing ghosts, know the numbers. Run a free speed test over Ethernet if possible — this tells you what your plan actually delivers. Then run it again over WiFi. The gap between the two quantifies your WiFi loss.
2. The usual suspects, ranked by frequency
2.1 Congestion (your network)
Someone in the house is streaming 4K, another is backing up to iCloud, your smart TV is auto-updating. Disconnect everything except your test device, re-run the test, compare.
2.2 WiFi signal
Walls, microwaves and neighbour networks kill 2.4 GHz throughput. If the signal is weak, move the router or switch to 5 GHz.
2.3 Router overheating or stuck
Routers are small Linux boxes. Reboot yours once every 30 days. Keep it cool and ventilated.
2.4 ISP throttling
Some ISPs shape heavy-usage accounts. If your speed is fine at 3 a.m. but terrible at 9 p.m., you're sharing a congested node — or being shaped.
2.5 DNS slowness
Slow "first byte" times often mean slow DNS. Try switching to 1.1.1.1 (Cloudflare) or 8.8.8.8 (Google).
2.6 Background processes
Windows Update, macOS software updates, Steam, OneDrive — all silently saturate your pipe.
2.7 Malware or rogue device
If speeds collapse even over Ethernet, one of your devices may be compromised. Check router logs for a single MAC hogging bandwidth.
3. The 10-minute fix protocol
- Reboot modem (30 s off).
- Reboot router (30 s off).
- Reboot test device.
- Plug into Ethernet, run a test, log numbers.
- Run a test over WiFi 2 m from router.
- Run a test over WiFi from your usual spot.
- Switch DNS to 1.1.1.1.
- Disable VPN and test again.
- Test from a second device.
- Compare to your plan's advertised speed.
4. When to call your ISP
If Ethernet speeds are under 70% of your advertised plan for 48 hours across multiple tests, open a ticket. Keep screenshots of your wifi-test.net results as evidence.
5. When to upgrade
If every test shows healthy numbers but your day-to-day still feels slow, you may simply have outgrown your plan. Streaming 4K on three screens + work calls + cloud backup can easily want 100–200 Mbps symmetric.
Conclusion
90% of "slow internet" is fixable in under 15 minutes with a reboot + test protocol. The 10% that isn't usually points to an ISP issue you now have evidence for. Run the protocol the next time speed drops — and keep the history.