What Chromecast Does and How It Connects
Chromecast is a small device that plugs into your TV's HDMI port and connects to your home WiFi network. Once connected, it receives video, audio, and photos from your phone, tablet, or computer and displays them on your TV screen. You control what plays using your device—Chromecast itself has no remote or buttons.
The connection works in two steps. First, your Chromecast device and your phone must be on the same WiFi network. Second, you open an app on your phone that supports Chromecast (like YouTube, Netflix, or Spotify) and tap the Chromecast icon. Your phone then tells Chromecast what to play, and Chromecast streams the content directly from the internet or from your device to your TV.
Key Takeaways
- Chromecast plugs into your TV's HDMI port and needs power; it works only when your TV is on and both devices share the same WiFi network.
- You control playback from your phone, tablet, or computer using apps that have the Chromecast icon built in.
- Your phone sends instructions to Chromecast, but Chromecast usually streams content directly from the internet rather than pulling it from your phone.
- Casting pauses if your phone loses WiFi or if you move out of range, but your TV will not lose the picture until Chromecast stops receiving the stream.
- Chromecast works with hundreds of apps including YouTube, Netflix, Spotify, Disney+, and Google Photos, but not all apps support it.
How Your Phone Communicates With Chromecast
When you tap the Chromecast icon in an app, your phone does not send the video file itself to your TV. Instead, your phone sends a small instruction message to Chromecast over WiFi. That message says something like "play this YouTube video" or "play this song from Spotify." Chromecast then goes directly to YouTube's servers or Spotify's servers and streams the content itself.
This is why your phone can be locked or put away after you start casting. Chromecast is no longer listening to your phone—it is listening to the streaming service. Your phone was only needed to send the initial command. If you want to pause, skip, or change the volume, you tap controls on your phone and it sends another instruction to Chromecast, but the video or music keeps coming from the internet, not from your device.
What Happens When You Cast From Your Phone's Screen
Some apps let you cast your entire phone screen to your TV instead of just casting the app itself. This is called screen mirroring or casting your screen. When you do this, your phone sends everything on its display—apps, web pages, photos, anything—to Chromecast, and Chromecast shows it on your TV in real time.
Screen mirroring works differently from app casting. Your phone is now actively sending the picture to Chromecast, so your phone must stay connected and awake. If your phone goes to sleep or loses WiFi, the picture stops. Screen mirroring also uses more battery and WiFi bandwidth than regular casting because your phone is doing the work of sending the entire display 30 times per second.
Why Your WiFi Network Matters
Chromecast needs a strong, stable WiFi connection to work smoothly. Both your phone and your Chromecast device must be connected to the same WiFi network—they cannot be on different networks or one on WiFi and one on a mobile hotspot. If your WiFi drops, Chromecast will stop playing within a few seconds.
The quality of your WiFi also affects streaming quality. If your network is slow or crowded (many devices using it at once), Chromecast may lower the video quality automatically to keep playback smooth, or it may buffer and pause. Moving your Chromecast closer to your WiFi router or reducing interference from other devices can help. If you are casting your phone's screen, a weak WiFi connection will make the picture lag or stutter.
What Apps Work With Chromecast
Hundreds of apps support Chromecast, but not all of them do. The most common ones are YouTube, Netflix, Disney+, Hulu, HBO Max, Spotify, Google Play Music, Pandora, and Google Photos. You can tell if an app supports Chromecast by looking for the Chromecast icon—it looks like a rectangle with curved lines in the corner, like a WiFi symbol pointing at a screen.
If an app does not have the Chromecast icon, you cannot cast from that app directly. However, you can still cast your entire phone screen to your TV using screen mirroring, though this uses more battery and bandwidth. Some apps block screen mirroring for copyright reasons, so even screen mirroring may not work with every app.
Setting Up Chromecast for the First Time
Plug your Chromecast into an HDMI port on your TV and connect the power cable to a USB port on your TV or to a wall outlet. Turn on your TV and switch to the HDMI input where you plugged in Chromecast. You should see the Chromecast setup screen appear on your TV.
On your phone, open the Google Home app (or Google Cast app on older devices). The app will detect your Chromecast and show it on the screen. Tap it and follow the prompts to connect Chromecast to your WiFi network. You will need to enter your WiFi password. Once Chromecast is connected, you can close the Google Home app and start casting from any supported app.
If Chromecast does not appear in the Google Home app, make sure your phone is on the same WiFi network as Chromecast. If you just plugged in Chromecast, wait a minute for it to start up. If it still does not appear, restart your phone and try again.
Troubleshooting Common Casting Problems
If the Chromecast icon does not appear in your app, first check that your phone and Chromecast are on the same WiFi network. Open your phone's WiFi settings and confirm the network name. Then check that Chromecast is powered on and connected—the light on the device should be solid white or blue, not red or blinking.
If casting starts but then stops or buffers, your WiFi connection may be weak. Move your Chromecast or router closer together, or reduce the number of devices using your WiFi. If you are casting your phone's screen and it is laggy, this is normal—screen mirroring requires more bandwidth than app casting. If the picture is pixelated or low quality, your WiFi speed may be too slow for the video quality you are trying to stream.
If your phone and Chromecast are on different WiFi networks (for example, your phone is on a guest network and Chromecast is on the main network), they cannot communicate. Make sure both are on the same network. If you have a 5GHz and 2.4GHz network with the same name, try connecting your phone to the same band as Chromecast.
Frequently Asked Questions
Can I use Chromecast without a smartphone?
Yes. You can cast from a tablet or computer using the same method. On a computer, you can cast from the Chrome browser by clicking the three-dot menu and selecting "Cast". You can also use voice commands with a Google Home speaker to cast to Chromecast without touching your phone.
Does Chromecast work if my phone is not on WiFi?
No. Your phone must be on the same WiFi network as Chromecast to send the casting command. Once Chromecast starts playing, it streams directly from the internet, so your phone can switch to mobile data or turn off WiFi—but you will not be able to control playback or send new commands.
What is the difference between Chromecast and Chromecast with Google TV?
The original Chromecast is a straightforward device that only receives casting commands from your phone. Chromecast with Google TV is a more advanced device that has its own remote, built-in apps, and a home screen. You can use either one to cast from your phone, but Chromecast with Google TV can also play content without a phone.
Can multiple people cast to the same Chromecast at the same time?
No. Only one device can cast to Chromecast at a time. If someone else tries to cast while you are already casting, their cast will take over and interrupt what you are watching. Some apps let you queue videos so multiple people can add to the playlist, but only one person controls playback at a time.
Does casting use a lot of data if I have a limited WiFi plan?
Chromecast streams from the internet, so it uses data the same way watching on your phone would. If you have a limited home WiFi plan, casting will count toward that limit. Streaming video uses more data than audio, and higher video quality uses more data than lower quality. You can lower the quality in most streaming apps to reduce data use.