A router cannot connect to the internet without a modem
A router is a device that shares an internet connection among multiple devices in your home or office. A modem is the device that receives the internet signal from your internet service provider and converts it into a form your devices can use. Your router needs that converted signal from the modem to do its job — without a modem, a router has no internet to share.
You can turn on a router without a modem, and it will work as a device. The lights will come on, the fans may run, and you can connect to its wireless network. But that network will not have internet access. Any device that connects to the router will see a network available but will not be able to load websites, stream video, or send email.
Key Takeaways
- A router needs a modem to access the internet; without one, it can broadcast a wireless signal but that signal carries no internet connection.
- Some internet service providers rent a combined modem-router unit, so you may not realize you have two separate devices.
- If your modem fails, your router will still turn on and broadcast a network, but devices connected to it will have no internet access.
- A router can work as a local network device without a modem — you can transfer files between computers on the same network — but internet-dependent tasks will not function.
What happens when you connect devices to a router without a modem
When you connect a computer, phone, or tablet to a router that has no modem, the device will show that it is connected to the network. The connection is real — the router is broadcasting a wireless signal and your device is receiving it. But the moment you try to open a web browser or use any service that requires the internet, the connection will fail.
The device will show "no internet" or "connected, no internet" in its network settings. You will not be able to send messages through email or messaging apps, load any websites, or stream content. The router itself is working correctly; it straightforward has nothing to share because the modem is not there to provide the internet signal in the first place.
When a modem and router are combined into one unit
Many internet service providers supply a single device that contains both a modem and a router built into the same box. These are sometimes called gateway devices or combo units. If you have one of these, you may not realize you have two separate functions happening inside the same plastic case.
If your service provider gave you a single device and you are wondering whether you need a separate modem, the answer is no — the modem function is already inside. However, if you want to use your own router instead of the one built in, you will still need the modem part of that unit to stay connected and powered on. The modem function cannot be turned off or removed without losing internet access.
Using a router as a local network device without internet
A router can perform one useful function without a modem: it can create a local network that allows devices to communicate with each other. If you have two computers in the same room and you want to transfer large files between them quickly, you can connect both to a router (without a modem) and move the files directly from one computer to the other.
This local network function does not require internet. The router straightforward acts as a hub that lets your devices talk to each other. However, this is a limited use case. For almost every other purpose — browsing the web, checking email, streaming video, or downloading software updates — you need the modem to bring internet into your home first.
What to check if your router has no internet
If your router is on but your devices show no internet connection, the problem is usually the modem, not the router. Start by checking the cables: the cable from the wall outlet should go into the modem, and a separate cable should run from the modem to the router. If either cable is loose or unplugged, reconnect it firmly.
Next, restart the modem by unplugging it for 30 seconds, then plugging it back in. Wait two to three minutes for it to fully restart — you will see lights on the modem change as it boots up. Then restart the router the same way. If the modem lights do not come back on after restarting, or if they show a red or amber color instead of green, contact your internet service provider — the modem itself may have failed or your service may be down in your area.
Renting versus owning your modem and router
Your internet service provider may rent you a modem, a router, or both. Rental fees typically appear as a monthly charge on your bill. If you own your own modem and router instead, you pay for them once upfront and have no monthly rental fee.
Whether you rent or own, the modem must come from a provider that your internet service provider supports — you cannot use just any modem with just any service. Your service provider can tell you which modems are compatible with your account. If you own your modem and it fails, you are responsible for replacing it. If you rent and it fails, your service provider will usually replace it at no extra cost.
Frequently Asked Questions
Can I use a router without a modem if I have a mobile hotspot?
Yes. If you connect a router to a mobile hotspot device (a phone or dedicated hotspot unit), the router can share that mobile internet with other devices. The mobile hotspot acts as the modem in this setup — it receives the internet signal and the router distributes it. This works but is usually slower and uses your mobile data plan.
What if my modem is broken but my router still has power?
The router will still turn on and broadcast a wireless network, but devices that connect to it will have no internet access. You will need to replace or repair the modem before internet service returns. Contact your internet service provider to report the problem and ask about a replacement.
Do I need both a modem and a router, or can I use just one?
If your service provider gave you a combined modem-router unit, you only need that one device. If you have a separate modem and router, you need both — the modem receives the signal from your service provider, and the router shares it with your devices. You cannot skip the modem.
Can I move my router to a different room without moving the modem?
Yes. Run an ethernet cable from the modem to the router in the new location. The modem must stay connected to the wall outlet where your service provider's line enters, but the router can be placed anywhere within cable distance or connected wirelessly if your modem supports it.