What Is Wi-Fi and How Does It Actually Work?
Wi-Fi is a way of connecting devices to a network using radio waves instead of cables. Your router converts data into a radio signal, your device receives it, and the whole exchange runs in both directions many times a second.
The name is not an abbreviation of anything. It was invented by a branding company, and the idea that it stands for “wireless fidelity” came afterwards.
Wi-Fi is not the internet
This is the most useful distinction to get straight, because it explains most home troubleshooting.
Wi-Fi connects your device to your router. Your internet connection links your router to your provider. They are separate links, and either can fail on its own.
- Strong Wi-Fi signal but no web pages loading means the problem is usually past the router, on the internet side.
- Weak or dropping signal in one room, while other rooms work, is a Wi-Fi problem.
Knowing which half is broken saves most of the time people spend restarting things at random. We cover the fixes in detail in our guide to fixing a Wi-Fi connection.
Bands: 2.4, 5 and 6 GHz
Wi-Fi runs on several frequency bands, and the trade off between them is consistent: higher frequency carries more data but travels less far and passes through walls less well.
| Band | Range | Speed | Congestion |
|---|---|---|---|
| 2.4 GHz | Longest | Slowest | Crowded |
| 5 GHz | Medium | Fast | Moderate |
| 6 GHz | Shortest | Fastest | Very clear |
2.4 GHz is crowded because it is also used by Bluetooth, microwave ovens, cordless phones and baby monitors. If your connection stutters when someone heats lunch, that is not a coincidence.
6 GHz is only available to devices supporting Wi-Fi 6E or Wi-Fi 7, and its short range means it works best in the same room as the router.
Channels
Each band is divided into channels. When neighbouring networks use the same channel, they interfere and everyone slows down.
On 2.4 GHz there are only three channels that do not overlap: 1, 6 and 11. In a block of flats with a dozen networks, most of that band is congested no matter what you do, which is one reason 5 GHz feels faster even at the same nominal speed.
What the Wi-Fi generation numbers mean
The Wi-Fi Alliance introduced simple numbers because the old names were unreadable.
| Name | Standard | Main change |
|---|---|---|
| Wi-Fi 4 | 802.11n | Multiple antennas, 2.4 and 5 GHz |
| Wi-Fi 5 | 802.11ac | Much faster on 5 GHz |
| Wi-Fi 6 | 802.11ax | Better performance with many devices at once |
| Wi-Fi 6E | 802.11ax | Wi-Fi 6 plus the 6 GHz band |
| Wi-Fi 7 | 802.11be | Wider channels, using several bands at once |
A detail worth knowing: Wi-Fi 6 improved how well a network copes with many devices rather than how fast a single device can go. In a house with thirty connected things, that matters more than peak speed.
Why the advertised speed is never what you get
Router boxes quote a theoretical maximum that adds together every band and assumes ideal conditions. Real throughput is lower because of distance, walls, interference, how many devices are active, and the capability of the device itself.
A phone with a single antenna cannot reach speeds that assume several. Your internet plan is also a hard ceiling: a very fast router does not make a slow connection faster.
Security
Wi-Fi security has gone through several generations, and the old ones are genuinely broken.
- WEP. Obsolete and crackable in minutes. Never use it.
- WPA and WPA2. WPA2 is still widely used and acceptable with a strong password.
- WPA3. Current, and resists the password guessing attacks WPA2 is vulnerable to.
A long passphrase matters more than complexity rules. On a public network, assume anyone could be watching unencrypted traffic, which is one of the main reasons people use a VPN.
Frequently asked questions
Does Wi-Fi work without internet?
Yes. A Wi-Fi network can connect devices to each other and to a printer or storage drive with no internet connection at all.
Why is my Wi-Fi slower than my internet plan?
Distance, walls, interference, an older device or an outdated router. Testing on a wired connection tells you whether the limit is Wi-Fi or the internet line.
Should I use 2.4 GHz or 5 GHz?
5 GHz when you are near the router and want speed, 2.4 GHz when you are far away or behind several walls. Most routers broadcast both and steer devices automatically.
Do Wi-Fi extenders reduce speed?
A traditional repeater usually halves throughput, because it receives and retransmits on the same radio. A mesh system with a dedicated backhaul avoids most of that penalty.
Is it safe to use public Wi-Fi?
Most traffic is encrypted by HTTPS, so the risk is lower than it once was. The remaining risks are fake hotspots and unencrypted connections, which is where a VPN is genuinely useful.
Where should I put my router?
Central, high and out in the open. Inside a cabinet, on the floor, or next to a metal appliance are the three most common mistakes.
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