Xfinity caps most of its plans at 1.2 terabytes a month and charges you if you go over. About 38,000 people a month search for this, and most of them are worrying about something that will never happen to them.

What 1.2TB actually is

A terabyte is a big number that means nothing until you turn it into hours.

• Netflix in HD uses roughly 3GB an hour. That is about 400 hours a month before you reach the cap.
• Netflix in 4K uses roughly 7GB an hour, so about 170 hours.
• A video call is about 1GB an hour.
• Music streaming is around 0.15GB an hour, which is negligible.

A household streaming HD television for thirteen hours a day, every day, would still be inside the cap.

Who actually goes over

Households that go over are usually doing one of three things: several people streaming 4K at once, running a console that downloads large games regularly, or backing up a lot of data to the cloud.

If none of that describes your house, the cap is not your problem and the unlimited add-on is not worth buying.

What it costs if you do go over

Xfinity charges for blocks of data over the cap, and unlimited data as an add-on runs about $30 a month on its own.

That $30 matters for another reason. If your gateway rental is bundled into xFi Complete at $25 a month, unlimited data is part of that bundle. Dropping the equipment to save $15 can put the $30 back on your bill.

Check what your rental is bundled with before you change anything.

How to check your own usage

Xfinity shows your usage in the app and in your account online, month by month.

Look at the last three months before deciding anything. If your highest month was under 600GB you are not close, and no add-on will change your bill for the better.

Questions people ask

How much is the Xfinity data cap?

Most Xfinity plans are capped at 1.2 terabytes a month. Unlimited data as an add-on costs about $30 a month on its own.

Is 1.2TB a lot of data?

Yes, for most households. It is roughly 400 hours of HD streaming a month, or about thirteen hours every day.

Who exceeds 1.2TB?

Households with several people streaming 4K at once, regular large game downloads, or heavy cloud backups. Most households never come close.

Should I buy unlimited data?

Check your last three months of usage first. If your highest month was well under the cap, the add-on adds $30 a month for nothing.