A router alone cannot connect you to the internet

A router is a device that shares an internet connection among your devices—phones, computers, tablets, printers. A modem is the device that brings the internet signal into your home from your internet service provider (ISP). You need both. The modem connects to the outside line; the router connects to the modem and then broadcasts that connection wirelessly to your devices.

Without a modem, a router has no internet signal to share. It will power on, it will broadcast a wireless network name, but that network will not connect you to anything. You can join it, but you will not be able to browse the web, stream video, or send email.

The only exception is if you are using the router purely as a local network device—to share files between computers in the same room, or to connect a printer that is physically near you. But that is not what most people mean when they ask this question.

Key Takeaways

  • A router without a modem can broadcast a wireless signal but cannot connect that signal to the internet.
  • Your modem receives the internet from your ISP; your router shares it among your devices.
  • Some internet plans include a combined modem-router unit, so you may have both functions in one box.
  • If your router stops working but your modem is fine, you can connect one device directly to the modem with an ethernet cable while you replace the router.

When you might think you do not need a modem

Some internet plans come with a combo unit—a single box that contains both modem and router functions. If you have one of these, you technically have a modem even if you do not think of it that way. Check your bill or the device itself; if it has a label from your ISP and handles both the outside connection and wireless broadcast, it is doing both jobs.

If you are moving to a new home or switching providers, your old router will not work with a new modem unless you buy a separate modem first. The modem is the part tied to your ISP account and your service plan. The router is generic—any modern router will work with any modem.

What happens if your router fails but your modem works

If your wireless network stops working but your modem still has lights on and is receiving signal, the router may have failed. You can test this by connecting one computer directly to the modem using an ethernet cable. If that computer can browse the web, your modem is fine and only the router needs replacing.

This is actually good news: you can order a new router and use the wired connection in the meantime. You do not need to call your ISP or replace the modem. Just plug the ethernet cable from the modem into your computer, and you will have internet while you wait for the new router to arrive.

How to tell which device is which

The modem is the device connected to the cable, fiber, or phone line that comes from outside your home. It usually sits near a window or where the line enters the building. It has one or two ports on the back labeled "Internet," "WAN," or "Line In."

The router is the device with multiple ethernet ports and antennas (or no visible antennas if it is a newer flat model). It connects to the modem with an ethernet cable. The router is what broadcasts your wireless network—the one you see when you search for WiFi on your phone.

If you have a combo unit, it will have both the external connection (for the ISP line) and multiple ethernet ports, plus it will broadcast wireless. Your ISP documentation or the device label will tell you which type you have.

What to do if you need internet but have no modem

If your modem has failed and you need internet right away, you have two options. First, contact your ISP and ask them to send a replacement modem. Most providers will mail one free or for a small fee, and it usually arrives within a few business days. They can often set up it remotely once it arrives.

Second, if you have a mobile phone with a data plan, you can use your phone as a hotspot to share its cellular connection with your other devices. This is not a permanent solution—it uses your phone's data allowance and is slower than home internet—but it works in an emergency. Go to your phone's settings, find "Hotspot" or "Personal Hotspot," turn it on, and other devices can connect to it like a WiFi network.

Renting versus owning your modem

Some ISPs charge a monthly fee to rent a modem; others let you buy your own. If you rent, the modem belongs to the ISP and they will replace it if it fails at no extra cost. If you own it, you pay once upfront but you are responsible for replacing it if it breaks.

Check your monthly bill to see if there is a "modem rental" or "equipment fee" line item. If there is, you are renting. If not, you own it or it came with your service plan. Owning is usually cheaper over time if you keep the same ISP for more than two or three years, but renting means you do not have to troubleshoot or replace hardware yourself.

Frequently Asked Questions

Can I use my old router with a new modem?

Yes. Routers are not tied to your ISP or service plan. Any modern router will work with any modem. Just connect the modem to the router with an ethernet cable, power both on, and the router will start broadcasting your network. You may need to log into the router to set up your WiFi name and password again.

What if my modem and router are in one box?

You have a combo unit. It does both jobs. If it stops working, you will lose both internet and wireless until it is replaced. You cannot separate the two functions. Contact your ISP for a replacement, or buy a new combo unit if you own the device.

Do I need to restart my modem and router in a certain order?

Restart the modem first and wait for all its lights to stabilize (usually 2 to 3 minutes). Then restart the router. This order matters because the router needs the modem to be ready before it tries to connect. If you restart them at the same time, the router may not find the internet signal.

Can a router work without power if it has a battery?

Most home routers do not have batteries. Some mesh WiFi systems or business routers do, but they still need the modem to be powered and connected to the ISP line. A battery in the router only keeps the wireless broadcast alive; it does not bring internet into your home. The modem always needs power from the wall.