5 Best Xfinity-Compatible Modems 2021

The Motorola MB7621 earns our pick for best Xfinity-approved modem for most people.

After comparing compatibility, user satisfaction, DOCSIS technology, and max wired speeds, we recommend the Motorola MB7621 as the best cable modem for most Comcast Xfinity plans.

We’re longtime renters of the Xfinity xFi Gateway modem and router, but the idea of saving money by buying our own routers pushed us to research dozens of cable modems. The xFi Gateway rental fee is $14 a month, which means you’ll potentially save $168 a year if you buy your own modem. (And router too, of course.)

Here’s how each one of these Xfinity-ready internet modems stacked up under our scrutiny.

Best Xfinity-compatible modems comparison
ModemPriceChannel bondingWired speedDetails
Motorola MB7621$77.98*24×8Up to 1,000 Mbps1View on Amazon
NETGEAR CM500$59.99*16×4Up to 680 Mbps2View on Amazon
ARRIS SURFboard SB8200$149.00*32×8 DOCSIS 3.0, 2×2 DOCSIS 3.1Up to 2,000 Mbps3View on Amazon
NETGEAR Nighthawk C7000$169.99*24×8Up to 960 Mbps4View on Amazon
NETGEAR Nighthawk CM1150V$249.99*2×2 DOCSIS 3.1Up to 1,000 Mbps5View on Amazon

Data effective 1/21/2021. Offers and availability vary by location and are subject to change.
Amazon.com List prices of $77.98, $59.99, $149.00, $169.99, and $249.99 (as of 1/21/2021 at 3:42 PM MST). Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.com at the time of purchase will apply to the purchase of this product. Reviews.org utilizes paid Amazon links.

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What’s with all the letters and numbers?
Finding an Xfinity-compatible modem is tough enough without having to deal with weird product names.

Unfortunately, the folks who make modems tend to use a combination of letters and numbers to differentiate between models. We’ll do our best here to simplify things and keep it straightforward, numbers and letters or not.

What you should know before buying a cable modem

Ready to swap your Xfinity modem out with one of your own? It’s a great way to put that equipment rental fee back in your pocket, so we don’t blame you.

But before you go out and buy your new cable modem, here’s what you should know.

Check compatibility.

Most importantly, make sure your potential new cable modem is compatible with your Xfinity internet service.

Xfinity lets you do this online with an easily searchable database of all supported modems. (You’ll need to provide your service address and internet plan speed to get access.)

Look for DOCSIS 3.0 or DOCSIS 3.1 technology.

DOCSIS, or Data Over Cable Service Interface Specification, is the technology that handles the transfer of data between your internet provider and your computer.

DOCSIS 3.1 is the latest version of this technology, but not all internet providers support it. If you’re eyeing a DOCSIS 3.1 cable modem that’s not backward compatible with DOCSIS 3.0, you’ll need to check with your internet service provider (ISP) to make sure it supports DOCSIS 3.1 tech.

But for now, DOCSIS 3.0 is still common and works just fine.

Channel bonding tells you how much bandwidth a modem can handle.

Channel bonding tells you how many channels a modem has for downloading and uploading data. Think of it like lanes on a highway: The more lanes, or channels, that you have, the more traffic, or data, that can get through.

When talking about channel bonding, the first number refers to the number of channels available for downloading data. The second number refers to how many channels are available for uploading data.

For example, a cable modem with 8×4 channel bonding features eight download channels and four upload channels. This modem should support an internet plan with up to 100 Mbps download speeds.6

More channels means faster speeds—but you’ll probably pay extra for them. So look for a modem with just enough channel bonding to support the internet speed advertised in your plan. You shouldn’t need more than that.

Make sure your cable modem supports your internet speed.

Your Xfinity internet plan comes with a promised maximum download speed. For example, the Performance Select plan comes with a promised max speed of 100 Mbps.

Another way to check what speed your internet plan comes with is to run a speed test. This gives you a more accurate view of what speeds you actually get. We recommend running several speed tests over the course of the day to get a bigger picture of how much your speed fluctuates at different times.

You’ll want to keep this max speed in mind when searching for a cable modem. If you buy a modem that doesn’t support your max speed, you’ll essentially waste money by paying for speeds you can’t get.

Motorola MB7621: Best for most Xfinity internet plans

A low price and speeds up to a gig make the MB7621 best for most Xfinity plans.

The Motorola MB7621 is an Xfinity-certified cable modem that comes with wired speeds of up to 1,000 Mbps.1 That covers pretty much every single Xfinity internet plan (aside from its extremely limited 2,000 Mbps plan).

At about 8 inches tall and 2 inches wide, the MB7621 is fairly inconspicuous. That’s perfect if you’re trying to keep electronic equipment from being the star of your home office.

Motorola MB7621 cable modem specs
ProductMotorola MB7621
ImageThe black Motorola MB7621 modem is the best modem for most Xfinity internet users
Source: Motorola.com
Price$77.98*
Wired download speedsUp to 1,000 Mbps1
DOCSIS versionDOCSIS 3.0
Channel bonding24×8
Telephone portNo
Warranty2 years
DetailsView on Amazon

Data effective 1/21/2021. Offers and availability vary by location and are subject to change.
Amazon.com List price of $77.98 (as of 1/21/2021 at 3:42 PM MST). Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.com at the time of purchase will apply to the purchase of this product. Reviews.org utilizes paid Amazon links.

Compatible Xfinity internet plans

Xfinity internet plans compatible with Motorola MB7621 modem
PlanPriceDownload speedData capDetails
Performance Starter$19.99*25 Mbps1.2 TBView Plan
Performance Select$34.99*100 Mbps1.2 TBView Plan
Performance Pro Plus$49.99*200 Mbps1.2 TBView Plan
Blast! Pro Plus$64.99*400 Mbps1.2 TBView Plan
Extreme Pro Plus$74.99*600 Mbps1.2 TBView Plan
Gigabit$84.99*1000 Mbps1.2 TBView Plan
Data effective 11/19/18. Offers and availability vary by location and are subject to change.
* For the first 12 months with a 1-year agreement.

NETGEAR CM500: Best budget modem

The CM500 is low-priced and highly rated.

If you don’t get Xfinity’s Gigabit plan, you can save a little money with the budget-priced NETGEAR CM500 modem. It supports wired internet speeds up to 680 Mbps.2

User reviews of the CM500 note that its installation was a breeze. So if you’re putting off getting your own modem because you’re not tech-savvy, give the CM500 a go.

Our only complaint about this modem (and all NETGEAR modems) is that it comes with only a one-year, limited hardware warranty.

NETGEAR CM500 cable modem specs
ProductNETGEAR CM500
ImageThe black Netgear CM500 modem for Xfinity internet
Source: Netgear.com
Price$59.99*
Wired download speedsUp to 680 Mbps2
DOCSIS versionDOCSIS 3.0
Channel bonding16×4
Telephone portNo
Warranty1 year
DetailsView on Amazon

Data effective 1/21/2021. Offers and availability vary by location and are subject to change.
Amazon.com List price of $59.99 (as of 1/21/2021 at 3:42 PM MST). Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.com at the time of purchase will apply to the purchase of this product. Reviews.org utilizes paid Amazon links.

Compatible Xfinity internet plans

Xfinity internet plans compatible with NETGEAR CM500 modem
PlanPriceDownload speedData capDetails
Performance Starter$19.99*25 Mbps1.2 TBView Plan
Performance Select$34.99*100 Mbps1.2 TBView Plan
Performance Pro Plus$49.99*200 Mbps1.2 TBView Plan
Blast! Pro Plus$64.99*400 Mbps1.2 TBView Plan
Extreme Pro Plus$74.99*600 Mbps1.2 TBView Plan
Data effective 11/19/18. Offers and availability vary by location and are subject to change.
* For the first 12 months with a 1-year agreement.

ARRIS SURFboard SB8200: Best for Xfinity gig plans

New DOCSIS 3.1 tech gives the SB8200 enough power for 2 Gbps speeds.

The SURFboard SB8200 uses newer DOCSIS 3.1 technology to support download speeds up to 2,000 Mbps (or 2 Gbps).3 That’s perfect if you’re rocking Xfinity’s Gigabit internet plan—or if you’re running your home business on its 2,000 Mbps Gigabit Pro plan.

We’ve recommended ARRIS’s SURFboard routers before, so it’s no surprise to us that the SB8200 made it into our top-five lineup.

ARRIS SURFboard SB8200 cable modem specs
ProductARRIS SURFboard SB8200
ImageThe white Arris Surfboard SB8200 modem is compatible with Xfinity
Source: Surfboard.com
Price$149*
Wired download speedsUp to 2,000 Mbps3
DOCSIS versionDOCSIS 3.1
Channel bonding32×8 DOCSIS 3.0, 2×2 DOCSIS 3.1
Telephone portNo
Warranty2 years
DetailsView on Amazon

Data effective 1/21/2021. Offers and availability vary by location and are subject to change.
Amazon.com List price of $149 (as of 1/21/2021 at 3:42 PM MST). Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.com at the time of purchase will apply to the purchase of this product. Reviews.org utilizes paid Amazon links.

Compatible Xfinity internet plans

Xfinity internet plans compatible with ARRIS SURFboard SB8200 modem
PlanPriceDownload speedData capDetails
Performance Starter$19.99*25 Mbps1.2 TBView Plan
Performance Select$34.99*100 Mbps1.2 TBView Plan
Performance Pro Plus$49.99*200 Mbps1.2 TBView Plan
Blast! Pro Plus$64.99*400 Mbps1.2 TBView Plan
Extreme Pro Plus$74.99*600 Mbps1.2 TBView Plan
Gigabit$84.99*1000 Mbps1.2 TBView Plan
Gigabit Pro$299.952000 MbpsUnlimitedView Plan
Data effective 11/19/18. Offers and availability vary by location and are subject to change.
* For the first 12 months with a 1-year agreement.
with No Term Agreement

NETGEAR Nighthawk C7000: Best modem and router combo

The C7000 modem and router combo saves you double the rental fees.

Xfinity’s xFi Gateway acts as both a modem and a router, so if you swap to your own equipment, you’ll need both. You can buy a modem and a router separately, or you can go for a combo like the NETGEAR Nighthawk C7000.

And, let’s face it. You could spend almost the same amount for just a modem. So the C7000 might save you more money in the long run.

The router also comes with excellent features like beamforming, which directs your Wi-Fi signal to your devices. (Think of it like lining up for a slam dunk versus blindly throwing 20 balls in every direction and hoping for a basket.)

NETGEAR Nighthawk C7000 cable modem and router specs
ProductNETGEAR Nighthawk C7000
ImageThe black Netgear Nighthawk C7000 modem for Xfinity internet
Source: Netgear.com
Price$169.99*
Wired download speedsUp to 960 Mbps4
DOCSIS versionDOCSIS 3.0
Channel bonding24×8
Telephone portNo
Warranty1 year
DetailsView on Amazon

Data effective 1/21/2021. Offers and availability vary by location and are subject to change.
Amazon.com List price of $169.99 (as of 1/21/2021 at 3:42 PM MST). Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.com at the time of purchase will apply to the purchase of this product. Reviews.org utilizes paid Amazon links.

Compatible Xfinity internet plans

Xfinity internet plans compatible with NETGEAR Nighthawk C7000 modem
PlanPriceDownload speedData capDetails
Performance Starter$19.99*25 Mbps1.2 TBView Plan
Performance Select$34.99*100 Mbps1.2 TBView Plan
Performance Pro Plus$49.99*200 Mbps1.2 TBView Plan
Blast! Pro Plus$64.99*400 Mbps1.2 TBView Plan
Extreme Pro Plus$74.99*600 Mbps1.2 TBView Plan
Data effective 11/19/18. Offers and availability vary by location and are subject to change.
* For the first 12 months with a 1-year agreement.

NETGEAR Nighthawk CM1150V: Best modem with phone jack

The CM1150V supports your landline phone plus gig internet.

For those of us still rolling old school with a landline phone, you might need a modem that comes with a phone jack.

Not surprisingly, that’s hard to find these days. But the NETGEAR Nighthawk CM1150V packs in all the features into one six-inch-high black box. You’ll get DOCSIS 3.1 technology that supports wired download speeds up to 1,000 Mbps, and you’ll get two phone jacks that are compatible with Xfinity Voice service.

Granted, all those features cost a pretty penny. So if cost-savings is what you’re after, you might try the cheaper ARRIS SBV3202—just be aware it supports speeds only up to 600 Mbps.

NETGEAR Nighthawk CM1150V cable modem specs
ProductNETGEAR Nighthawk CM1150V
ImageThe black and silver Netgear Nighthawk CM1150V modem for Xfinity internet
Source: Netgear.com
Price$249.99*
Wired download speedsUp to 1,000 Mbps5
DOCSIS versionDOCSIS 3.1
Channel bonding2×2 DOCSIS 3.1
Telephone portTwo
Warranty1 year
DetailsView on Amazon

Data effective 1/21/2021. Offers and availability vary by location and are subject to change.
Amazon.com List price of $249.99 (as of 1/21/2021 at 3:42 PM MST). Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.com at the time of purchase will apply to the purchase of this product. Reviews.org utilizes paid Amazon links.

Compatible Xfinity internet plans

Xfinity internet plans compatible with NETGEAR Nighthawk CM1150V modem
PlanPriceDownload speedData capDetails
Performance Starter$19.99*25 Mbps1.2 TBView Plan
Performance Select$34.99*100 Mbps1.2 TBView Plan
Performance Pro Plus$49.99*200 Mbps1.2 TBView Plan
Blast! Pro Plus$64.99*400 Mbps1.2 TBView Plan
Extreme Pro Plus$74.99*600 Mbps1.2 TBView Plan
Gigabit$84.99*1000 Mbps1.2 TBView Plan
Data effective 11/19/18. Offers and availability vary by location and are subject to change.
* For the first 12 months with a 1-year agreement.

Recap: The 5 best Xfinity-approved modems 2021

Our pick for the best Xfinity-compatible cable modem is the Motorola MB7621, thanks to its low price and support for wired speeds up to 1,000 Mbps. But if you don’t need gig speeds, the NETGEAR CM500 can save you a bit of cash with its budget-friendly price.

For anyone looking for the latest DOCSIS 3.1 technology and the ludicrous speeds it brings, the ARRIS SURFboard SB8200 and NETGEAR Nighthawk CM1150V are top-rated contenders. And those looking to replace the Xfinity xFi Gateway without having to buy a router as well should consider the NETGEAR Nighthawk C7000 modem and router combo.

  1. Motorola MB7621: Best for most Xfinity internet plans, $77.98*, wired speeds up to 1,000 Mbps.1
  2. NETGEAR CM500: Best cheap cable modem, $59.99*, wired speeds up to 680 Mbps.2
  3. ARRIS SURFboard SB8200: Best for gig internet plans, $149.00*, wired speeds up to 2,000 Mbps.3
  4. NETGEAR Nighthawk C7000: Best modem and router combo, $169.99*, wired speeds up to 960 Mbps.4
  5. NETGEAR Nighthawk CM1150V: Best modem with phone jack for Xfinity Voice, $249.99*, wired speeds up to 1,000 Mbps.5

Data effective 1/21/2021. Offers and availability vary by location and are subject to change.
Amazon.com List prices of $77.98, $59.99, $149.00, $169.99, and $249.99 (as of 1/21/2021 at 3:42 PM MST). Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.com at the time of purchase will apply to the purchase of this product. Reviews.org utilizes paid Amazon links.

Now that you know about the best Xfinity cable modems, check these out next.

Compare Xfinity internet prices in your area.

Know what to expect when it comes to Xfinity internet.

READ THE COMCAST XFINITY INTERNET REVIEW

Sources

  1. Motorola, “Motorola MB7621,” 2020. Accessed January 26, 2021.
  2. NETGEAR, “High Speed Cable Modem (CM500),” 2021. Accessed January 26, 2021.
  3. ARRIS, “SURFboard® DOCSIS® 3.1 Gigabit Cable Modem,” 2021. Accessed January 26, 2021.
  4. NETGEAR, “Data Sheet C7000 | Nighthawk® AC1900 WiFi Cable Modem Router,” 2020. Accessed January 26, 2021.
  5. NETGEAR, “Data Sheet CM1150V | Nighthawk® CM1150V Multi-Gig Speed Cable Modem for XFINITY® Voice,” 2018. Accessed January 26, 2021.
  6. Linksys, “Does Your Modem Match Your Broadband Service?,” 2021. Accessed January 27, 2021.