How to Check If Someone Is Using Your WiFi

~/sheets/someone-using-my-wifi.md
Is Someone Stealing Your WiFi?
If your internet is slow, your data usage is high, or you suspect unauthorized access, someone might be connected to your WiFi without permission. Here is how to check and fix it.
Signs of Unauthorized WiFi Access
Internet is noticeably slower than usual — run a speed test to measure
Your router lights blink when no one is using the internet
Unknown devices appear in your router's connected devices list
Higher than expected data usage on your ISP bill
How to Check Connected Devices
Log into your router admin panel (usually 192.168.1.1 or 192.168.0.1)
Look for "Connected Devices," "Client List," or "DHCP Clients"
You'll see a list of device names, IP addresses, and MAC addresses
Identify each device — if you see unknown devices, someone is on your network
How to Remove Unauthorized Users
Change your WiFi password immediately — this disconnects everyone. All your devices will need to reconnect with the new password.
Enable WPA3 encryption (or WPA2 if WPA3 is not available). Never use WEP — it can be cracked in minutes.
Disable WPS — WiFi Protected Setup has known vulnerabilities.
Enable MAC filtering — only allow specific devices to connect.
Hide your SSID — your network won't show up in WiFi scans (but dedicated attackers can still find it).
Ongoing Security
Change your WiFi password every few months. Keep your router firmware updated. Use a strong password — at least 12 characters with mixed case, numbers, and symbols. For a complete checklist, read our WiFi Security Checklist. Run a port scan to check for exposed services on your network.
Last updated: April 2026