Wi-Fi, mobile data and speed.
"The internet is slow!" Is it really the internet, the Wi-Fi, the phone or the website? Today you'll learn how to understand speed, fix common Wi-Fi problems, and stay safe on networks.
Speed in simple words
- Internet speed is measured in Mbps (megabits per second).
- Download speed: how fast things come to you (videos, websites).
- Upload speed: how fast you send (video calls, uploading reels).
- Ping / latency: delay in milliseconds; matters for video calls and gaming.
| Activity | Rough speed needed |
|---|---|
| WhatsApp, browsing | 1–5 Mbps |
| HD video streaming | 5–10 Mbps |
| Video calls | 3–10 Mbps (upload matters) |
| Uploading long videos | Higher upload speed helps |
Note: MB (megabytes) is file size, Mb (megabits) is speed. 8 bits = 1 byte, so 80 Mbps downloads about 10 MB per second.
Wi-Fi vs mobile data
| Wi-Fi (broadband) | Mobile data (4G/5G) |
|---|---|
| Home or office connection through a router | From mobile towers |
| Usually unlimited or high limits, stable | Daily or monthly limits |
| Range limited to around the router | Works anywhere with coverage |
Fixing slow Wi-Fi
Test it: use speedtest.net or fast.com near the router and in the problem room.
Wi-Fi safety
- Change the router's default admin password and use a strong Wi-Fi password (WPA2 or WPA3).
- Don't share your home Wi-Fi password widely; use a guest network for visitors.
- On public Wi-Fi (cafés, stations), avoid banking and never enter passwords on strange login pages.
Your speed test shows 90 Mbps next to the router but 5 Mbps in the bedroom. What's the likely cause?
The plan is fine at the router. Move the router or add a mesh/extender.
Which should you change first when setting up a new router?
Default passwords are easy for others to guess.
Your task (15 min)
Run speed tests next to your router and in the farthest room. Restart the router and try again. If you can, log into the router and change the default admin password.
Lesson 6 complete!
You understand Mbps, Wi-Fi vs mobile data, how to test speed and fix common problems, and Wi-Fi safety. Next: email like a professional.
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