Why does my stream keep buffering?

A stream buffers when video reaches your screen more slowly than it plays. The usual reason is that the speed at the TV, not at the router, is below what the stream needs, or keeps dipping below it. Test on the device that buffers and compare the result with the service's figure: Netflix asks for 5 Mbps for 1080p and 15 Mbps for 4K. If the speed is fine, the cause is Wi-Fi stability, the app, other traffic in the house, or the service itself.

What buffering actually tells you

Streaming apps download a few seconds to a few minutes of video ahead of what you're watching. While data arrives faster than the video plays, that buffer stays full. When it arrives more slowly, the buffer drains, and when it's empty you get the spinning wheel.

Before that happens, most apps drop to a lower quality to keep playing. The symptom tells you how bad things are:

• Picture goes soft, then sharpens: speed dipped briefly and the app adapted. That's normal behavior.
• Long wait to start, then fine: a slow start, often from the app, the device or a busy service.
• Stops mid-play again and again: speed keeps falling below even the lower qualities, or the connection is dropping in and out.

Step 1: test the speed where the TV is

A speed test on your phone in the kitchen tells you very little about a TV two rooms away. Test on the TV if its browser can open a speed test, or use its network settings test. Otherwise, hold your phone right next to the TV on the same Wi-Fi network and test there.

Then compare the result with what the stream needs:

• Netflix recommends 5 Mbps for 1080p and 15 Mbps for 4K.
• YouTube recommends 5 Mbps for 1080p and 20 Mbps for 4K.
• Disney+, HBO Max, Apple TV and YouTube TV ask for 25 Mbps for 4K. 4K streaming requirements by service has the full list.

As a rule of thumb, aim for at least 1.5 times the figure at the TV. The requirement is a steady speed, and Wi-Fi rarely holds steady. Run the test two or three times. One good result between dips proves little.

If speed at the TV is too low: fix the Wi-Fi

When the router room gets 300 Mbps and the TV gets 12, the plan isn't the problem. TVs tend to sit behind cabinets, against walls and next to other electronics, and their built-in Wi-Fi is often weaker than a phone's.

In order of how much they help:

1. Ethernet to the TV. A cable removes Wi-Fi from the equation entirely, and it's the most reliable fix. Why Wi-Fi is slower than Ethernet explains the difference.
2. A mesh node or access point near the TV. It works almost as well when a cable isn't practical.
3. Moving the router higher, more central and out of cabinets.
4. Using the 5 GHz band if the TV is fairly close to the router. 2.4 GHz reaches further but is slower and more crowded.

If speed is fine but it still buffers

A test that shows plenty of speed at the TV points somewhere else.

Only one app buffers. If Netflix stutters while YouTube plays fine on the same TV, the line is probably fine. Close the app fully and reopen it, update it, and update the TV's software. If that fails, sign out and back in or reinstall the app. Check the service's status page or social accounts too, since big releases and live events can overload a service.

Everything buffers, but only at certain times. Busy evenings strain both your home and your provider's local network. Run the same test at a quiet time and again when it buffers. If the evening result is far lower even next to the router, the slowdown is outside your home.

Someone else is using the connection. A console downloading a game update, a computer syncing to the cloud, or three other streams can take everything that's spare. Pause big downloads and test again. Most consoles and computers let you schedule updates overnight.

A VPN is on. A VPN sends the stream through another server, often far away, and some services block known VPN addresses. Turn it off and compare. How a VPN affects speed covers what to expect.

The device is struggling. Older streaming sticks and smart TVs can run out of memory or processing power, especially with 4K or after months without a restart. Fully power the TV or stick off and back on. If it buffers on every app while a phone streams the same show fine, the device may be the weak link.

Quick fixes to try in order

1. Restart the app, then the TV or streaming stick.
2. Pause downloads, backups and updates on other devices.
3. Test the speed next to the TV and compare it with the service's figure.
4. Lower the playback quality, or check the app's data-saver setting. A capped setting can look like a slow connection.
5. Restart the modem and router. Power both off, wait 30 seconds, then start the modem first.
6. Connect the TV with Ethernet, or add a mesh node near it.
7. If it only buffers on one service, check that service's status and update its app.

For Netflix specifically, Netflix's speed requirements explains what each quality level needs.