In computer networking, a modem is a device used to send and receive digital signals over different types of analogue mediums such as TV cable, or telephone lines.

Many people consider modem and router as the same device whereas, in reality, they are not.

A router is a device which connects a bunch of devices in your home/office together to form a network and routes traffic between those devices. A modem, on the other hand, serves as the link between your home network (the one created by a router) and the internet.

There exist some modem/router combos, aka gateways. These are the devices that act as a modem and routers at the same time. Their router part creates a home network and their modem part connects that network and all its devices to the internet.

These 2-in-1 combos are useful when you don't have a lot of space, but they don't give you as much customization as standalone modems and routers do.

So now that the confusion has been cleared, let's come to the main topic:

Should You Rent A Modem from your ISP, or buy your own?

First, let's talk about why people hate ISP-rented modems.

Why ISP-rented Modems Suck

1. Most ISPs charge a monthly fee (usually between $5-$10), in addition to the internet fee, for the modems they rent.

Although this doesn't feel a lot, it is when you see things in the bigger picture.

Here's a small example: Most of us try an ISP for at least 12-18 months before switching. This way, you pay $60-$90 in one year and never own anything. On the other hand, when you buy your own modem, you just make a one-time payment, and it remains yours forever.

2. A large number of modems that ISPs rent (especially cable modems) are actually outdated in terms of technology.

To fully explain this one, we have to understand DOCSIS technology first.

The DOCSIS (Data Over Cable Service Interface Specification) is the technology standard that provides data transfer over cable TV systems. The latest version of those standards is DOCSIS

3.1 which can provide Gigabit internet speed.

But there's a catch though.

In order to fully enjoy this much bandwidth, you'll need a DOCSIS 3.1 cable modem too. Unfortunately, none of the major ISP provides you with a DOCSIS 3.1 modem (at the time of writing). This is another reason why many people hate 'em.

On the other hand, there are a number of 3.1 cable modems out in the market such as Motorola SB 8600, Netgear CM1000 etc.

Why Buying A Modem May Not Be Good For You

So far we've learned two big advantages of buying your modem. First, it'll be a one-time cost and second, the modem given by ISP is outdated.

Now we'll talk about another side of the coin: Why you should stick with your ISP-rented modem.

1. You own a DSL modem.

Not all internet connections use cable TV systems. There exist some DSL-based connections for which you need a DSL modem. If you happen to be one of those, don't bother getting a new modem because you won't see a huge difference.

2. DOCSIS 3.1 coverage is not in your area.

Although ISPs in the US are trying hard to provide Gigabit internet in all cities, there are some areas in which this facility hasn't reached yet. That's why it's better to ask your ISP first. If you happen to live in one of those areas, the latest DOCSIS 3.1 modems will be useless for you.

3. Here's the last point in the favor of ISP modems. Not all ISPs allow you to use 3rd party cable modems.

Well, a majority of ISPs are compatible with a majority of cable modems, but there exist some exceptions. That's why different ISPs, like Comcast Xfinity and Time Warner, have published a list of compatible modems on their respective websites.

On top of that, some ISPs charge modem-rent fees even if you use your own modem.

If that's the case, it's better to not buy your own modem.


OK, so now we've talked about both pros and cons of using an ISP modem, here comes the conclusion time.

What should you do: Use a rented modem or buy your own?

Actually, it depends.

If your area has DOCSIS 3.1 support and if your ISP supports a 3rd-party modem, it's good to have it. Otherwise, stick with the one that your ISP has given.