Internet Speed Requirements for Firestick Streaming
Minimum speed requirements
SD streaming: 5 Mbps minimum. HD streaming: 10 Mbps minimum. 4K streaming: 25 Mbps minimum. These are per-device — if multiple devices stream, you need more.
How to test your speed
Use the Speedtest app on your Firestick, or test on a phone/computer connected to the same WiFi. Test at the location where your Firestick is.
WiFi vs Ethernet for Firestick
WiFi works for most people, but Ethernet provides the most stable connection. You can use a USB-to-Ethernet adapter with Firestick 4K Max for a wired connection.
Improving WiFi for Firestick
Move your router closer to the Firestick. Use 5GHz WiFi instead of 2.4GHz. Remove physical obstacles between router and Firestick. Consider a WiFi extender if signal is weak.