Modem vs. Router: What Each Does and How They Differ

How are modems and routers different?

The difference between a modem and a router is that a modem connects to the internet, while a router connects devices to Wi-Fi. It's easy to get the two devices mixed up if your internet service provider (ISP) rents both to you as part of an internet package. Knowing the difference between a modem and a router and how each work can help you be a better consumer, and you'll save money by purchasing equipment, rather than paying a monthly fee to an ISP.

What Modems Do

What it Can Do

  • Connects to your ISP(Internet Service Provider).

  • Compatible specifically with the ISP.

  • Converts the signal from them to a universal one that your computer can use.

What it Can't Do

  • Create a local network.

  • Run WiFi.

  • Connect multiple devices to the internet.

A modem connects the source of your internet from your ISP and your home network, whether you use a cable provider such as Comcast, fiber optics from FIOS, satellite such as Direct TV, or a DSL or dial-up phone connection. The modem connects to the router —or directly to a computer — using an Ethernet cable. Modems are different for each type of service; they are not interchangeable.

Modem on a desktop
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ISPs rent modems to subscribers for a monthly fee, but cable modems are available for sale at relatively low prices. Monthly rental rates are around $10 extra per month. If you plan to keep the same service for a year or more, buying a cable modem that costs about $100 quickly pays for itself. FIOS-compatible modems are hard to come by, so in that case, it's worthwhile to rent one from Verizon.

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What Is a Modem in Computer Networking?

What Routers Do

What it Can Do

  • Creates a local area network(LAN).

  • Allows you to split your internet connection to all of your devices.

  • Hosts WiFi.

  • Run a firewall.

  • Connect to a VPN.

What it Can't Do

  • Connect directly to the internet.

  • Decode the signal from your ISP.

A router connects to a modem and creates a private network in a home, office, or business such as a coffee shop. When you connect a device to Wi-Fi, it connects to a local router.

Routers connect smart devices, including smartphones, smart speakers such as Amazon Echo, and smart home products such as light bulbs and security systems. Wireless routers also stream content to laptops and mobile devices through Netflix, Hulu, and similar services, without using cables.

Wireless router in the foreground, person using a laptop in the background
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Some ISPs offer routers for rental, but to get the latest technology, it's worth buying one. Buying a wireless router means you can choose the model that's best suited for your home or office or has advanced features for gaming and other activities if you need them.

Modem and Router Combo Devices

There are also modems with integrated routers that perform both functions. These modems can be rented from your ISP or purchased directly. These combo devices might include a VoIP function if you have a cable, internet, and phone package.

Combination devices are not usually the best option. If one part breaks, the whole thing is useless, and you can't upgrade one device at a time. Still, if you don't need the latest and greatest tech, buying a combo modem and router is convenient.

What Are Mesh Networks?

In some scenarios, one wireless router isn't sufficient to cover an entire home or office due to a vast space or one with a complicated layout, multiple floors, or impenetrable walls. To avoid dead zones, purchase range extenders that connect to the router and expand its reach. However, that usually means less bandwidth in areas near the extender, which translates into slower browsing and download speeds. That's when investing in a mesh network might make sense.

A Wi-Fi mesh network consists of one primary router and several satellites, or nodes, that relay the wireless signal from one to the next, like a chain. Rather than extenders that communicate only with the router, mesh network nodes communicate with each other and there's no loss of bandwidth, so the signal is as powerful as if you were next to the primary router. There's no limit to how many nodes you can set up, and you can manage it using a smartphone. Whether you need a range extender or a mesh network depends on the size of the space and how much bandwidth is required.

What to Choose and When

Modem

  • Decodes the signal from your ISP.

  • Connects you directly to the internet.

  • Doesn't set up a local network.

  • Is not responsible for WiFi.

Router

  • Establishes a local network.

  • Creates and manages WiFi.

  • Splits your internet connection to your devices.

  • Does not decode the signal from your ISP.

  • Requires a modem to connect to the internet.

You're always going to need both a modem and a router to set up a home network. If you're just connecting a single computer to the internet with a wire, you can use only a modem. There's no case where you can use just a router. You'll always need a modem to decode the signal from your ISP.

When you're looking to speed up your network, the router is usually what you want to focus on. It has its own bandwidth limits, and it distributes the signal to all of your devices. Your router creates and manages your WiFi.

The modem is usually not causing a slow connection. Generally, you'll get one from your ISP, and they'll give you one suitable for your subscription. That said, if you plug in your computer directly to your modem and run a speed test, you can test whether you're getting your advertised internet speed. If not, contact your ISP. There may be a connection issue or your modem may be outdated. In which case, they'll most likely let you swap it out for a newer model.