Step 1: Test and describe the problem
Run the speed test on the device that feels slow, where you normally use it. Then match what you see:
| What you notice | What to check first |
|---|---|
| Everything is slow; download is low | Steps 2–4 |
| Videos buffer on one TV only | WiFi to that TV (step 3) |
| Download is fine, pages still hang | Ping and packet loss (step 5) |
| Calls are choppy, video freezes | Upload, jitter and packet loss (step 5) |
| Lag only when others are online | Ping under load: bufferbloat test |
| Slow every evening | Congestion (step 6) |
Step 2: Rule out the device
- Restart the device.
- Close apps and browser tabs; pause downloads and cloud sync.
- Turn off any VPN and test again.
- Test on a second device in the same spot. If the second device is fast, the first one is the problem: update it, check for malware, or try a different browser.
Step 3: Find out whether it’s WiFi
Plug a laptop into the router with a cable and test. Then test on WiFi next to the router, and again in the slow room.
- Wired fast, WiFi slow: it’s your WiFi. Move the router, use 5 GHz, or add mesh coverage. See how to test WiFi speed.
- Wired slow too: continue to step 4.
Step 4: Check your home network
- Find other traffic. Look for updates, backups and streams running on other devices. Many routers’ apps show which devices are using the most data.
- Restart the modem and router. Unplug both for 30 seconds; power the modem first, then the router.
- Check the cables between the wall, modem and router. Reseat them and swap any that look damaged.
- Check the status lights on the modem against your provider’s guide. A warning light can mean a line problem.
- Check for an outage on your provider’s website or app.
Retest with a cable after each change.
Step 5: Look past Mbps
If speed looks fine but the internet still feels bad, look at the other numbers in your result:
- High ping (over 100 ms to a nearby server): see how to reduce ping.
- High jitter (over 30 ms): see how to reduce jitter.
- Packet loss (over 1%): see how to fix packet loss.
- Big increase in ping under load: that’s bufferbloat; smart queue management on your router usually fixes it.
Step 6: Contact your provider
If wired results are consistently well below your plan’s typical speed, or you see packet loss on a cable straight to the modem, the problem is likely outside your home. Before you call:
- Collect wired results from several days, including evenings. Our guide on how to test internet speed includes a simple log.
- Note that you have restarted the equipment, checked cables and tested with other devices disconnected.
- Ask them to check the line, signal levels and equipment at their end, and whether your modem is suitable for your plan.
Retest
After any fix, run the test again under the same conditions as your first test. If the numbers improve, you have found the cause. If they don’t, move to the next step.