Technology Explained

Modem vs. Router: What’s the Difference?

Megan Ellis 04-02-2020

While we sometimes use modem and router interchangeably when talking about our home internet hardware, these two devices are not the same thing. In fact, their roles are very different.


So what is a modem? What’s a router? And what is the difference between a modem and a router? Here’s what you need to know about these two devices.

What Is a Modem?

modem connection illustration

A modem converts the incoming and outgoing signals between an ISP and a user’s home or workplace. The modem’s job involves converting these signals to compatible formats, which enables the transmission of data required to connect to the internet.

An ISP sends data using a variety of signals (radio, electric, satellite, fiber-optic, etc), while computers and electronic devices use digital signals. This means that the modem is needed to essentially translate and convert the signals. This allows these two endpoints to communicate.

The conversion process involves the modulation and demodulation of signals—hence the name of the device: a portmanteau of the term “modulator-demodulator”.


Depending on your internet connection type, the type of modem you need varies. For example, for cable internet, you need a cable modem 5 Questions to Ask When Purchasing a New Cable Modem With just a bit of research, you can buy your own cable modem and save hundreds of dollars over a few years. Read More . Meanwhile, LTE internet requires an LTE modem and DSL internet requires a DSL modem.

Regardless of the type of modem, however, the core purpose remains the same.

Without a modem, your computer or phone would not be able to send and receive the data needed to connect to your internet service. The hardware establishes and maintains your internet connection.

However, a standalone modem can only connect one device to the internet at a time. That’s where a router comes in…


What Is a Router?

home network connected by router illustration

A router creates a local network of devices, allowing these devices to send data to your modem and each other. A router technically wouldn’t be required if you wanted to only connect one device to the internet. However, the majority of modern homes have multiple devices that use the internet, such as smartphones, tablets, and multiple PCs.

For these devices to seamlessly transmit data in your local network, you need a router. It routes data and traffic between devices (hence its name).

Your router does this by assigning local IP addresses to each device, so that the data ends up in the right place. Otherwise, the same data would go to every device on the network.


Modern routers include a built-in switch and hub, providing the ports needed for each of your devices to have an uninterrupted connection to the web. Hubs and switches are also available as standalone devices—but this is usually for the workplace where many more users or devices need to connect to the network.

Routers can technically also function without the internet if you only want to share files between your local devices. This means you can use a router without a modem to share files from your PC to your printer, or to send files between two computers on the same local network. However, your router needs to connect to your modem to provide internet access.

You can find out more about routers in our guide on routers and what they do How Does a Router Work? A Simple Explanation Routers may seem complicated, but they're actually quite simple. Here's a quick guide to routers, what they do, and how they work. Read More .

Modem Vs Router: What’s The Difference?

network with modem and router example


The essential difference between a modem and router is their role when it comes to connecting you to the internet. While the modem is the bridge between your home and the internet, the router is responsible for creating your local network within the home.

You could imagine the router as a traffic guard. It helps vehicles (your devices) gain access to the bridge (modem) that leads to the internet. The router makes sure that every device stays in its lane and doesn’t interrupt the connection of other devices or intercept their data.

Another difference between a modem and router is that a modem has a single, public IP address. However, a router assigns a variety of local IP addresses for communication within the network.

Then, there’s there the necessity that each device plays when it comes to connecting to the internet. No matter what, a modem is necessary to connect to the internet. That’s why small modems are built into devices like smartphones, to translate the internet connection provided by your mobile service provider.

Without a router, a modem can still connect to the internet. The same is not true the other way around. Furthermore, a modem is used solely for connecting to the internet, whereas a router can technically be used without the internet to create a home network between devices.

Modem/Router Combinations

modem-router combined device
Image Credit: Misha Feshchak/Unsplash

The line between modems and routers has become so blurred in the minds of consumers for a reason. After all, many manufacturers sell modem/router combination devices. These come with both a modem and a router built into a single piece of hardware.

As technology advances, these combined devices have become increasingly common. Many modern households use a combined modem and router. Meanwhile, small mobile or portable modems also combine both technologies into one device.

However, it’s important to understand the distinction between modems and routers since they are still often sold as standalone devices. You don’t want to buy one when you actually need the other. Furthermore, it can be cheaper to buy them as standalone devices when it comes to upgrading specific aspects of your home internet network or replacing old modems and routers.

What About 5G Routers and Modems?

With the hype around 5G, more people are wondering whether they’ll need special modems and routers to connect to this internet technology.

Like with any other type of internet connection, you will need a compatible modem to connect to 5G internet What Is 5G? Here's How It'll Make Mobile Internet Faster and Better Feel your mobile internet is too slow? 5G is the next generation of mobile internet, and will make mobile data faster than ever. Read More . 5G-enabled smartphones and tablets have these modems built into them. But those who want to use a 5G connection for their home will need a 5G modem. These are already available, along with 5G modem-router combinations, from 5G ISPs and certain retailers.

Some companies also offer 5G CPEs (customer-premises equipment) with a built-in modem and router to connect customers to 5G networks.

Older routers should still work with 5G modems. But you may want to upgrade your router to take advantage of the full speed of 5G. Slower single-band routers may create a bottleneck for a fast 5G internet connection.

However, this will largely depend on your internet plan and how fast your 5G connection actually is. Don’t go upgrading your devices just yet until you know that 5G is available in your area, the details of your plan, and which devices are compatible.

Understanding Your Internet Wi-Fi

Now that you understand the roles of modems and routers better, you may still be wondering about other aspects of your home internet network. For example, where does Wi-Fi come in?

To find out more about Wi-Fi standards, and how they play a role in your connection to the internet, read our guide on understanding Wi-Fi The Most Common Wi-Fi Standards and Types Explained Confused by the various Wi-Fi standards in use? Here's what you need to know about IEEE 802.11ac and older wireless standards. Read More .

Related topics: Modem, Router.

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  1. Paul
    May 27, 2020 at 9:52 pm

    I can't believe that in America, of all places, that people actually BUY modems and/or routers. In New Zealand the ISP's provide them free of charge. Have done for at least 18 years.