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What is Kbps?

R. Kayne
R. Kayne

Computer data architecture is based on the binary system of using ones and zeros in a string of eight "bits" to form different characters. Each string of eight bits is called a byte. 8 bits = 1 byte = 1 character as described by the order of the 8 bits of data

For example, the capital letter "K" is expressed in binary bits as "01001011." In traditional usage, 1,024 bits of data equals a kilobit, while 1,024 bytes equals a kilobyte. Kbps always refers to kilobits, while the designation of KB/sec refers to kilobytes.

1024 bits = 1 kilobit

1024 bytes = 1 kilobyte = 8 kilobits

1024 kilobytes = 1 megabyte = 8,192 kilobits

An ADSL modem can deliver Internet speeds of up to 3,000 kbps.
An ADSL modem can deliver Internet speeds of up to 3,000 kbps.

Although these figures are still used in many applications, the International System of Units (SI) provides a slightly different official definition. In order to make the prefixes align with those used in the metric system, they define 1 kilobit as 1,000 bits; 1,024 bits is called a kibibit. The traditional measurements are still most commonly used for computer memory, whereas most networking applications use the SI measurements.

DSL filter.
DSL filter.

One of the most ubiquitous devices to rate data transfer speeds in terms of kilobits per second is the standard dial-up modem. At 56 kbps it provides the least expensive, albeit the slowest, method of connectivity to the Internet. As an example, DSL modems deliver speeds starting at 144 kbps and ranging upwards of 3,000 kbps, sometimes expressed as 3.0 mbps (megabits per second).

Many high-speed ISPs (Internet Service Providers) continue to describe their services in terms of kilobits, rather than using kilobytes or megabits. This makes it easy for potential customers to compare transfer rates against their existing dial-up modems. When rates are expressed in units other than kbps, it can be confusing to the dial-up shopper.

While a dial-up modem is capable of speeds close to 56 kilobits per second, line noise, network traffic and other interference can cut data transfer speed significantly. Under the best circumstances, a 56 kbps modem will generally operate at about 53 kbps or 6 KB/sec. Here are some conversions that might help when looking at high-speed services:

567   Dial-Up
14418  (3x faster)
38448  (8x faster)
76896  (16x faster)
1,100137.51.0 (20x faster)
1,500187.51.5 (27x faster)
3,0003752.90.36(54x faster)
6,0007505.80.73(108x faster)

High-speed services might include DSL, cable and satellite. VDSL (Very high-speed Digital Subscriber Line) can deliver speeds of up to 100 mbps. Generally, the faster the transfer speed, the higher the monthly charge. Household consumers switching from dial-up modems to high-speed access will likely call upon the services of a company providing speeds in the ranges listed above.

With the emphasis on Internet connectivity in work, schools and the home -- and the growing applications requiring higher throughput -- understanding kbps will no doubt become handy in determining the best value for your money when switching ISPs.

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Discussion Comments


@wlc33: You have a really fast connection, so you would have a 30mbsps, roughly.


I am currently using internet off a 25 GB per month range. I was thinking of joining a different company and they're offering me 25mbps a month for a cheaper price. Which one is higher, 25GB or 25mbps?


I have a satellite connection to the internet which claims to deliver up to 12 mbps service with a 15 GB monthly allowance. My problem is this: I run out of download allowance about five days into the month by watching one hour of streaming video a day.

I have contacted the tech guys from where I get the video and they informed me that they stream at 3000 kbps for HD and 768 kbps for standard definition. If I figure for the highest use at these stated speeds how long should it take to use up my 15 GB allowance? Any ideas? What would the formula to figure this out look like?


@anon67276: If you are doing your testing inside your home for cell phone reception then you have other issues to consider. Inside the home there are many things that will interfere with a clear reception. Step outside and it will change drastically.

This is why many people will often buy a cell phone antennae for outside/inside the home. It will grab signals outside the home and rebroadcast from an AP inside the home so your signal is much better.


Measuring in bits is worthless. If your ISP says you get 10mbps (megabits per second) down. Then you take that

10,000,000 bits per second / 8 bytes per bit


1,250,000 million bytes per second

1024 bytes in a kilobyte

1024 kilobytes in a megabyte

1,048,576 bytes per megabyte

1,250,000 bytes per second /

1,048,576 bytes per megabyte

= 1.19 MBps


I've become interested in Kbps after dealing with AT&T home service and now with my iPhone. For the former service that I clocked around 200-300 Kbps regularly, I changed to Comcast for speed I need to watch netflix movies. It did peeve me that AT&T advertised "speeds up to 1.5 MB" but they do not also warn that speeds vary widely depending on (basically excuses).

No problems with Comcast and high marks for service. Funny thing, when I use my iPhone at home (home-based business), iPhone depends entirely on wireless! I am paying $30 a month for Internet service that cagily leeches off a more efficient cable connection. It tries to do this when I'm out and about as well.

I found out the true At&T speed today since my router died (I think or maybe it needs a vacation from having to service my iPhone's needs) and have run two random sets of speed checks for ten minutes each. The downloads were as follows: 498, 570, 0, 22, 1016, 70, 773. Later test: 728, 1114, 721, 931, 0, 0, 0, 734, 703, 0, 621, 793, 0, 0, 0, 0, 0. Seems horribly spotty to me and explains the poor response, pages timing out frequently.

Why I am angry is that AT&T advertises or implies speed as part of their benefit and it is a lie. Yeah, I know, it's advertising, but I feel if I am going to have crappy reception because of my location from whatever it is I am located too far from, then I should pay proportionately less per month to make up for this. Just my opinion


to wlc33: download speed times 0.122 gives you kilo bytes/per second. or roughly divide it by eight.


Thanks, this post really helped. I was having trouble grasping the 10MB/sec that was being offered to us by our hosting company, also our internet service provider. The extreme bandwidth is needed for streaming internet radio. This helped a lot.


I believe this is an incredible and very informative site. It has helped me understand many things about the computer technology (and I thought Medicine was tough). My hat is off to those truly involved in this field. I do appreciate what you all do. I recently had to connect an ACN video phone and confronted problems with the digital transmission of which the highest kbps is 512 but the images continue freezing frequently. I have to either use 128,256 or 384 kbps; how ever the higher I go the, clearer is the picture/image but the images continue freezing. I wonder if it is the Fire wall that is impairing the optimal transmission since it is connected to my office computer modems and routers.


I have tested my download speed and come up with 30751 kbps and up load speed of 2357 kbps. How does that compare to the advertised speed of the internet service provider and advertised speeds of routers expressed in mbps? Do you divide by 1000 or some other number?

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    • An ADSL modem can deliver Internet speeds of up to 3,000 kbps.
      By: Petr Malyshev
      An ADSL modem can deliver Internet speeds of up to 3,000 kbps.
    • DSL filter.
      DSL filter.