Difference between Megabit and Megabyte: How not to fall into Error

What is the difference between Megabit and Megabyte: what do the abbreviations Mbps (or Mb / s or Mbit / s) and MB / s (or MByte / s) refer to.

When referring to the capacity of a data link and, therefore, to the maximum speed for data transfer, Megabits per second or Mbps (or Mb / s or Mbit / s) are used as the measurement unit.

The lowercase letter “b” has a precise meaning and indicates that a multiple of the bit ( binary digit ) is used, that is the elementary unit of information processed by a traditional processor (the values ​​0 and 1 are the representation of logical values ​​that the bit can assume).

Megabits per second: a unit of measure for network capacity and throughput

Operators and, in general, in telecommunications and information technology, Megabits per second are used to describe the maximum transmission speed or the transmission capacity of the line (channel capacity).

The maximum transmission speed is a constant of the line and can differ, even significantly, from what is published by the providers on a commercial level.

20 Megabit ADSL connections or 100 Megabit fiber connections presented commercially as such means that on the card they can allow data to be transferred, respectively, up to 20 and 100 Mbps (in the exchange or on the road cabinets there are DSLAM devices that allow you to manage these peak performance: they perform the functions of the numeric line of access and modulation to and from the telephone pair of the user; see Map of Telecom switchboards and road cabinets ).

In practice, the Mbps performances that can actually be obtained are generally reduced compared to those advertised because they are a function of parameters such as attenuation and signal/noise ratio (SNR), which are in turn closely linked to the distance from the DSLAM, to the structure of the line, to the presence of noise, to the problem of crosstalk on copper pairs (in the case of FTTC connections – Fiber-to-the-Cab connections on the copper network portion that reaches the subscriber’s modem router from the road cabinet) and, again, network congestion, the bandwidth available in practice on the DSLAM, along the path and by the destination system.

The problem of crosstalk will be largely mitigated as soon as AGCOM and operators agree on the use of vectoring in Italy, thanks to which even the real estate units not too close to the cabinet (300-600 meters) will be able to obtain remarkable performances on FTTC fiber.

The network capacity, therefore the value relating to the data transmission speed that can be theoretically or practically reached, does not coincide with the throughput or with the “actually used” transmission capacity.

Also, the throughput is measured in megabits per second, but it is only an index of ‘ “actual” usage of the link capacity.

The Megabit per second is a multiple of the bit and corresponds to the transmission of 1,000,000 bits per second. However, depending on the capacity of the connection you are dealing with, you can use other multiples of the bit: kbps (1,000 bits per second) or Gbps (1,000,000,000 bits per second).

THEGigabits per second or Gbps are used to refer to the capacity of the most modern FTTH ( Fiber-to-the-Home ) fiber connections already available today as well as future FTTH evolutions: XG-PON, XGS-PON, and NG-PON2.

Gbps are then increasingly used to measure the capacity of a LAN. In the local area, using devices (routers, switches, clients, …) and “ad hoc” Ethernet cables, you can activate 10GbE (10 Gigabit Ethernet), or even 100GbE (100 Gigabit Ethernet) links: Ethernet cables: differences and characteristics .

The various speed tests allow you to estimate the available bandwidth in kbps, Mbps, or Gbps. They, therefore, help to evaluate the link capacity, but the result can be considered sufficiently reliable if and only if the network was not engaged in upload/download data transfers.

If you are interested in verifying the downstream data rate, you can use the Fast.com speed test, perhaps the fastest and most immediate around.

Difference between Megabit and Megabyte

The Megabyte is a unit of measurement of information or quantity of data, one of several multiples of the byte.

Many still today confuse between Mbps (or Mb / s) and MB / s, believing that they are the same units of measurement. Nothing more wrong.

While kbps, Mbps, and Gbps are used to measure the link capacity, when for example, you download a file with the browser, the download speed is expressed in bytes per second (KB / s or MB / s).

This is correct because, in this case, the information transferred in the unit of time is measured with reference – for example – to the weight of a file.

Eight bits are used to encode a single alphanumeric character. The byte, which expresses a sequence of 8 bits, has, therefore, historically become the basic element in computer architectures and the unit of measurement of memory capacity.

When we talk about the capacity of a hard disk, an SSD, an SD card, a USB stick, an external hard disk, we are talking about bytes (usually, today, gigabytes or terabytes), certainly not bits.

The bit, in fact, is not an adequate unit of measure to express the number of characters that can be stored in a storage unit.

When you right-click on any file in Windows and choose Properties, the General tab reads the size of the selected object in bytes or in multiples, not in bits.

Since the byte is made up of a sequence of 8 bits, this can take on 256 possible values ​​(i.e., 2 8 ). The famous ASCII character table is made up of 256 entries, each corresponding to one of the characters that can be formed with a different combination of the 8 bits that make up the byte.

On the QWERTY keyboards with an Italian layout, for example, the braces do not exist, but by typing the combination of keys ALT + 123 and ALT + 125, you can insert them instantly.
To go from bits to bytes, therefore, simply divide by 8.

A connection with a capacity of 20 Mbps can transfer up to 2.5 MB / s (20 divided by 8) or 2,500 KB / s; a connection from 100 Mbps up to 12.5 MB / s.

Megabytes per second (MB / s) immediately give an idea of ​​the amount of information that can be transferred in a second: if you could use all the 100 Mbps of a fiber link, you could take a document of 12 from the network, 5 Megabytes in just one second; with a 1 Gbps FTTH fiber link, a 125 Megabyte file in just one second.

By typing megabit megabytes in the Google search box, you will access a converter that allows you to immediately switch from Megabits per second to Megabytes per second and vice versa (with the possibility of using the various multiples of bits and bytes).

This converter gives an idea of ​​the performance of each connection while this online calculator (unfortunately for some time, it requires free registration) helps to estimate how long it takes to transfer a file – download or upload – depending on the connection speed and the file size.

Obviously, the greater the link capacity, the greater the bandwidth that can be shared between the various devices connected to your local network.

It goes without saying that if the downstream data rate for your Internet connection barely reaches 7 Mbps, it will be nearly impossible for multiple client devices to simultaneously access 1440p video.

The popular Netflix video streaming service requires at least a connection capable of offering 3 Mbps downstream for content in standard SD quality (720p), 5 Mbps for Full HD (1080p), and 25 Mbps for 4K UHD content (and Netflix applies a series of optimizations to reduce the “weight” of streaming).

By using specific codecs, in fact, better performance can be obtained: for example, with the Google WebM VP9 codec, the necessary bandwidth for a 4K 2160p video at “just” 17.3 Mbps and for a 1080p video at 2.6 Mbps but a lot of depends on the content provider and the hardware/software configuration of the client device.

Obviously, for streaming audio content only, the requirements drop a lot: just think that, for example, Spotify uses a bitrate of 96 kbps (therefore 0.096 Mbps) for listening to music in normal quality (default setting for the app intended for devices mobile) going up to 320 kbps or 0.32 Mbps for Premium subscribers (“maximum quality”).

What are mebibits and mebibytes?

Someone may have heard of megabits or mebibytes as well. What are they? Do we want to complicate the picture? Not at all.

The megabits per second (Mibit / s) are the unit of measurement of the capacity of a link per unit of time expressed according to the binary prefix.

A value expressed in kikibit / s or Mibit / s obviously expresses a difference with respect to that indicated in kbps, Mbps, KByte / s, and MB / s.

A mebibit corresponds exactly to 1,048,576 bits, while when we talk about a Megabit, we conventionally refer to 1,000,000 bits, as seen above. Similarly, one mebibyte equals 1,048,576 bytes (one byte = 8 bits), while one megabyte is matched to 1,000,000 bytes.

The percentage error in the mode of expression of the measurement of the data transfer rate in Mbps and MB / s is, therefore, approximately 4.9% compared to mebibit and mebibyte.