Why do I get less Internet Speed than promised?


Internet speedThis question often puzzles people. Why do I never get the promised Internet speed? For example, say, I’ve an Internet connection that promises 1 Mbps speed, then why does it take more than 1 second to download a file of about 200 KB size? Or else, why do I get the download speed of only about 30 KB per second with a 1Mbps connection? Well, there could be several reasons for this deficiency in what you expect (or are promised) and what you get in terms of the Internet speed. In this article, I’ll briefly touch upon these reasons. But, the first and foremost reason is that generally people are confused (and are not aware) as to how Internet speed is measured in one specific unit while the download speed (of say downloading a file of size 200 KB) is measured in a different unit, which causes mismatch between the two due to differing units used. Let me explain this first.[Also see: Online speed test for your broadband connection.]

Difference between bits and bytes leads to confusion:

Internet speed is measured in terms of bits per second. One bit is the smallest unit of information that a computer can understand, it is either 0 or 1. So, the Internet speed would be expressed like this:

  • 1 Kbps = 1000 bits per second
  • 1 Mbps = 1000,000 bits per second
  • 1 Gbps = 1000,000,000 bits per second

Here, K, M and G stand for a thousand, a million and a billion, respectively.

On the other hand, file sizes are measured in terms of Bytes. Here, 1 Byte = 8 bits.

Moreover, in computing the file sizes using binary mode, K, M and G have slightly different meanings, as explained below:

  • 1 KB ( 1 KiloByte) = 1024 Bytes (appx. 1000 Bytes)
  • 1 MB (1 MegaByte) = 1024 KB (appx. 1000 KB)
  • 1 GB (1 GigaByte) = 1024 MB (appx. 1000 MB)

Therefore, the file sizes, which are expressed in terms of KB, MB and GB, do NOT use the same unit such as Kbps, Mbps and Gbps as are used for Internet speed.

While file sizes are measured in Bytes, the Internet speed is measured in bits. And, as I mentioned earlier, 1 Byte = 8 bits.

Checking your Internet Speed
Checking your Internet Speed

Therefore, most of the times, people get confused due to the use of different units for measurement for file size and Internet speed, though both these units use similar symbols. Let me explain this by using the aforesaid example that I quoted in the beginning of this article. If I’ve an Internet connection that promises 1 Mbps speed, then why does it take more than 1 second to download a file of about 200 KB size?

So, let’s examine the reason. When the Internet speed is 1 Mbps, this means you’re getting 1 million bits (1000,000 bits) per second. To convert them into Bytes, we’ve to divide it by 8. So, we get 125,000 Bytes in second. This is about 122 KiloBytes or 122 KB; remember we’ve to divide Bytes by 1024 (and NOT by 1000) to get KiloBytes or KB.

Therefore, 1 Mbps Internet speed will give you a maximum of about 122 KB size file download from the Internet. Accordingly, if the file size is 200 KB, it would take about 2 seconds even if you’re able to get the promised full speed of 1 Mbps.

In general, you’ve to divide the Internet speed by 8 to get what file size you can download in one second. Here is a quick calculation for the most common Internet speeds:

Internet Speed File Size transfer per second
256 Kbps About 31 KB
512 Kbps About 62 KB
1 Mbps About 122 KB
2 Mbps About 244 KB
3 Mbps About 363 KB


This removes the biggest confusion that people generally have in their mind about not getting Internet speed as promised.

Other reasons of getting less Internet speed than promised:

OK. Got it. But, what if I am still getting much less Internet speed than what is promised? For example, if I’ve an Internet connection of 1 Mbps, why do I get only about 30 KB file size in 1 second when I should be in a position to download a file size of about 122 KB in 1 second?

Well, I fully agree that most of the times, the actual speed is much less than the promised speed, even after taking into account the difference between bits and bytes.

In fact, I’ve myself seen worse performance than what is mentioned above. For example, earlier I had Reliance NetConnect+ Broadband (wireless) data card for my Internet usage. Reliance is a popular Internet Service Provider in India. The aforesaid plan has the official speed of 3.1 Mbps. But, can you believe when I tell you that at times I used to get the actual speed of equivalent to only 1 KB file size per second?!!?? Of course, there is no typing mistake here. To be honest, sometimes I would get 40-50 KB (KiloBytes) in one second, but mostly the speed would be less than 10 KB in one second, and sometimes even less than 1 KB in one second!!! They tried their best to correct the speed, but unfortunately they couldn’t do it; may be because of location variations. [Due to this reason, I changed my ISP and switched over to the state-run MTNL Triband Wifi Internet. Luckily I’m getting the Internet speed in the promised range, though there are some occasional disconnections.]

So, how do you explain such big difference in promised speed and actual speed?

Well, some of the possible reasons are as under:

(1)    What your ISP promises you is the maximum Internet speed, and not the minimum speed. Therefore, the actual speed may always be less than the maximum speed promised.

(2)    Your ISP may have its infrastructure setup for a specific number of users. They take into consideration the fact that not all the users would be connecting to the Internet at the same time. So, they make a reasonable guess of how many users would be connecting at a given time simultaneously. But, many times, the actual number of users connecting to the Internet simultaneously is much more than their expectations, due to which the total bandwidth gets shared by more number of people, thereby each user getting less bandwidth (and speed) than promised.

(3)    There may be bottlenecks or defects in the infrastructure at the ISP end (or it might have become obsolete, since Internet is a fast changing technology).

(4)    Then, there are a whole bunch of unscrupulous and greedy ISPs who promise you the moon to entice you to become their subscribers. But, they don’t have that much capacity to serve, or their subscriber number has exceeded their installed capacity, and they just don’t want to increase the capacity, or it is taking time to enhance the capacity.

(5)    The ISP quotes a standard Internet speed for everyone in all localities (may be, same speed throughout the country as a whole). But, the actual speed may differ from place to place within their full coverage area due to several factors.

(6)    If you use cable Internet, the same cable is shared by several people in a neighborhood. So, your speed may reduce accordingly if more people are trying to use the same limited bandwidth. Of course, this is no excuse for the ISP to promise higher speed.

(7)    If you use wireless Internet (such as WiFi), speed may be affected adversely deep inside the buildings due to walls and other solid structures.

(8)    If you use DSL technology (telephone and Internet through the same copper wire), there may be problems in the underground cables. For example, a few years back, due to heavy rains, underground cables near my locality got affected badly and I was not able to get a reasonable Internet speed. The ISP had to change the damaged cables.

(9)    You may have your own internal network (though a wired or wireless router) with one Internet connection, and more than one computers or devices (such as your mobile phones) may be connected at the same time to the same Internet connection. This is likely to divide your Internet speed accordingly. In such a scenario, even a broadband connection may appear like a dial-up connection.

These are only some of the reasons. It is not an exhaustive list. Therefore, generally, you may not get the promised Internet speed. However, there is a limit beyond which a shortfall in Internet speed cannot be explained. That’s the time to say good-bye to your existing ISP. This is what I had to do when I changed my ISP from Reliance NetConnect+ Broadband to MTNL Triband. [Also see: Improve broadband Internet connection speed through SG TCP Optimizer.]

TG Facebook Comments

  • M.Abdul Wahab


    Atlast the end came for my confusion….Really a good article…Nice Job….

    I have another doubt after reading this article.

    What is the difference between Bandwidth and Internet Speed ?

    Please Guide me……I am waiting for your reply or article….