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What does a gigabyte limit on my internet plan really mean?


I have a 2.5 gb/per month internet browsing plan. What does it mean? Does it
include download & upload?

As ISPs face ever-increasing internet use, they’re often looking for ways to
either throttle how much their subscribers use or charge more to those who use
a lot.

One of the ways that they do that is by imposing caps on your data transfer.
A certain amount of transfer is included as part of your plan and if you go
over that, you pay more or run into other restrictions.

But just what does “data transfer” mean?


The internet is all about data

When you use the internet, everything that you do can be broken down in to data being transferred across the connection provided by your ISP.

“… it’s actually very difficult to measure how much data the computers on your home network are actually transferring …”

The terms “up” and “down” are used to characterize what direction the data is being transferred. Up, as in “upload”, means data transferred from your computer or your local network across your internet connection to a resource out on the internet. Down, as in “download”, means the reverse: data transferred from some resource out on the internet, across your internet connection, and to your machine.

Let’s say that you visit a web page, such as this one. Your web browser sends a request for the page by transmitting data up your internet connection to the Ask Leo! web server. That server responds by sending the data that makes up this page back down your internet connection to your computer where the browser interprets it and displays the page.

Everything counts

Everything that you do on the internet somehow gets down to data being sent up or down your internet connection.


It’s pretty easy to realize that when you download a file from the internet … well, that’s a download (although there was a small amount of information sent up the connection to request that the file to be downloaded).

And web pages, as I described above, are all about sending requests up and getting web pages back.

Desktop email programs request and download email, and of course, upload when they send.

Instant messaging programs transmit data up and down the internet connection.

Online backup programs upload your data to be backed up and synchronization programs like DropBox, Evernote, and the like may well download that data to other computers which you have set up for the purpose.

And of course, online video or audio, no matter how it’s accessed, is a download of fairly large amounts of data.

And that’s probably the hardest part of this entire equation.

Knowing how much you use

It turns out that it’s actually very difficult to measure how much data the computers on your home network are actually transferring up and down the internet connection.

By far, the best measurement is the one kept by your ISP; unfortunately, not all of them make it easily available. (Kudos to Verizon Wireless for making this information easily accessible.)

When the information isn’t available, the more practical approach is to understand what’s “big” and what’s not.

Most emails are small, unless they have large attachments. Fortunately, email programs typically show you the message’s size.

Similarly, downloads are often listed with their size so you can choose whether or not to download.

Video tends to be the most difficult because there are different encoding methods that use different amounts of data to represent different levels of quality.

A little math

As a rule of thumb, a “GB” or gigabyte is a billion bytes, or 1,000 MB (megabytes), 1,000,000 KB (kilobytes) or 1,000,000,000 bytes.

So that 2.5GB cap means that you can transfer 2.5 billion bytes of information before hitting that cap.

How much is that? 1/2 of a normal 4.7GB DVD full of data, or about three and a half full CDs.

Even then, that’s difficult to translate into information being uploaded and downloaded, but at least it gives you an order of magnitude to go by.

And finally, I can’t say whether the transfer cap includes both uploaded and downloaded data. That’s actually up to the ISP to determine. You should ask.

In most cases, it’s download, because we download much more data than we upload. But whether they combine the two numbers, or use only the download, or in the case of large uploaders, use the larger of the two – that’s unclear.

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6 comments on “What does a gigabyte limit on my internet plan really mean?”

  1. Another thing to remember when watching videos or listening to music is the difference between “streaming” and “downloading”. When streaming, every time you watch/listen, it downloads the entire video/song. So, if you find some video on YouTube, and watch it several times, or show it to your friends, you might end up turning that 10MB video into 50MB of traffic. The same thing holds true for Internet radio stations, although audio needs much less data than video.

  2. My ISP (“3”) make it fairly simple – they have an approximation of your usage on their site – although, I have had arguments with them about it in the past.
    They also (usually) send you a message when you have 20% of your allowance left, and another when you run out completely.
    My method is to actually watch the network connection status window. Bit geeky, and sometimes a little alarming (especially around ‘patch tuesday’), it lets me make sure I’m not using more than I should.

  3. What does a Gig limit mean? Breach of contract for a start. Take AT&T as an example. Recently your DSL Transfer rate has been cut in half, then quartered. And now an Octopodic rate schedule is included with caps in their model. Forgotten is the original hook, line and sinker of faster than bloated cable, still with no specific data rates mentioned unless held in contempt of court.

    The Only crisp clear market iron clad contract promise was unlimited internet access. With a less clear promise of a data rate that may or may not be four Gigabits per second down and a half a gigabit per second up.

    What the hell is this gigabit crap? Eight bits to a byte and a stop byte. My that did shrink in size rather quickly. Sure sounded impressive. What next? Down to double dial up speed, access between 9am-10pm, no piggy backing, bundling, or shackled smartphone Wi-Fi internet access. Thumb print unlocking for router portal connect.

    Give me a break. They have sucked the competitive market down to two sources Cable or The phone Co. Both friendly helpful community minded corporate friends of the consumer always willing to contribute to the common good of subscriber bases.

    When is the last time you saw a mention of internet2 already superseded by internet3? The vast amazing light speed low ping Oceans of bandwidth handling of multicolor phasing laser phiber optic handling.

    Hmm, got pretty quiet with bargains in Malibu to be snatched up didn’t it. Trust me, your ISP irregardless of which of two you have has only one piggyback in mind and you can start to squeel like a pig right now.

  4. An other data transfer rule of thumb when using video communications like Skype is:
    One minute of video is about one megabyte of total data transfer.
    Rough and ready but gets you in the ball park.

  5. If you are on (say) You Tube website and watching a video, and simultaneously use Video Downloader in Firefox to download it so you can watch it from your hard drive later, are you downloading the bytes twice, doubling your usage? If yes, how can you avoid the doubling of download?

    Yes you are. The only way not to is to pick only one method and do that only.


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