How to distinguish from megabits megabyte

What the bytes and bits

Bit - this is the minimum unit of digital information in a binary system. In 1 byte - 8 bits. By themselves, these units are small, so in everyday life we ​​often meet them with prefixes kilo, mega- and giga-.

Contrary to expectations, these prefixes are not hiding 10 in the third, sixth and ninth degree. If we were talking about grams, then it would have been easy: in a kilogram - 1000 grams, megagram (and this word isorthographic dictionaryJust instead typically use a "ton") - one million grams. But with bytes situation is much more complicated, because they simultaneously exist in decimal and binary systems of measurement.

In Russia, unit values ​​established by a regulationRF Government Resolution dated October 31, 2009 № 879 "On Approval of the terms of the quantities permitted for use in the Russian Federation" RF Government. And the document says:

• 1 KB = 1024 bytes;
• 1 MB = 1024 KB;
• 1 GB = 1024 MB.

Outside Russia, the question looks different, and it is related to International Units (SI). In the latest edition of the brochure

The International System of Units (SI) International Chamber of Weights and Measures states that prefixes like kilo, mega-, giga- They should be used strictly for the units of the decimal system. Accordingly, 1 megabyte - is 1000 kilobytes, and not 1024. The publication notes that for use in the binary system the International Electrotechnical Commission offered its prefixes kibi-, mebi-, gibi-.

But for the bits in the Government Decree no specific explanation, therefore, no differences at the international level: 1 kilobit = 1,000 bits. For those who can not come to terms with this fact, in the case are the prefixes for binary systems of measurement. Thus 1024 bits equal 1 kibibitu.

What abbreviations to use

bytes

So that you do not try to reduce the unit at random, in Russia there GOSTGOST 8.417-2002 State system for ensuring the uniformity of measurements (ICG). Unit values ​​(corrected)Which regulates how and what to write. According to the document:

• 1024 bytes = 1 kB;
• 1,048,576 bytes = 1 MB;
• 1,073,741,824 bytes = 1 GB.

By the way, to visit recognize that consoles kilo, mega-, giga- used in binary wrongly. In this case, for kilobytes, in which 1000 bytes works International System of Units, and "B" is mandatory title:

• 1000 bytes - 1 kB;
• 1 million bytes - 1 MB;
• 1 billion bytes - 1 GB.

This writing is found as an example in interstate standardsStandard IEC 60027-2-2015 letter designations used in electrical engineering. Part 2. Telecommunications and electronics lettering. The document also regulates reduction with prefixes for binary units:

• 1 kibibyte KiB = 1;
• 1 mebibytes MiB = 1;
• 1 = 1 gibibyte GiB.

In everyday life, you are unlikely to meet designation, but will at least know what they are.

As far as international abbreviations to denote kilobytes equal to 1000 bytes as 1 kB. Megabytes and gigabytes decimal become MB, and GB. In the binary system, 1 = 1 kibibyte KiB, 1 MiB mebibytes = 1, 1 = 1 gibibyte GiB, and abroad, these units are used actively.

bits

Since the bits used international measurement system, they are reduced without the frills - to kbps, Mbps, Gigabit, and so on. As for the prefixes for binary units, 1 = 1 kibibit KIBIT.

Abroad, kilobits, megabits and gigabits designated as kbit, Mbit and Gbit. If you talk about bits in the binary system, then in the course are Kibit, Mibit and Gibit.

Why do you need to know

Understanding the difference between bits and bytes and megabytes and megabits should help when choosing a tariff with the necessary speed Internet connection or any kind of storage device to store information: solidInternal or external hard drive, but at least the USB drive and MP3-player.

When choosing the tariff

ISPs typically indicate the information rate "up to 50 Mbit / s" or "100 Mbit / s". And without understanding the difference between a bit and a byte is easy to fall into the trap. In the ignorant man may be an illusion, that the 100-megabyte file he downloaded per second.

But a little mathematical magicAnd it becomes obvious that we are talking only about 12.5 megabytes per second (just divide by 8 - so much of bits contained in one byte).

For example: you need to download a file weighing 750 megabytes. This is the same that fold 6000 megabits of data (6000 MB ÷ 8 = 750 MB). To download it at a rate of 50 Mbits / s is required 2 minutes and at 10 Mbit / s - 10 minutes.

When choosing the drive

If the difference between the amount of kilobytes, megabytes and kilobytes in binary and decimal systems did not exist, everything would be easy. But it is, and it's all complicated, since the real capacity varies depending on what the particular manufacturer invests in kilobytes and the country in which it is located. Depending on the approach, the difference in memory capacity can be substantially increased and in proportion to increase disk capacity.

Compare 1 kilobyte in binary and decimal systems - it is 1024, and 1000 bytes, respectively. But 1 terabyte - that's 1 099.5 gigabytes and gigabytes of 1000. A difference of nearly 100 gigabytes.

Manufacturers often define the storage capacity in the decimal system, and the system sees it in binary, and the memory capacity may be lower than that to which you expect. Therefore, on the packaging drives foreign manufacturer is better to look at the capacity gibibyte or tebibaytah - GiB and TiB, they know that exactly calculated in the binary system of measurement.

How to convert from one unit of measurement to another

It's simple. To put in megabits megabytes, multiply the number by 8.

MB X = Y × 8 MB

To put megabits to megabytes, divide the number by 8.

X MB ÷ 8 = Y MB

To find out how much time (in seconds) required to download it, put it in megabits size and divide the resulting number by the speed.

(X 8 × MB) ÷ Y Mbit / s = t

To find out how many megabytes to gigabytes, multiply the number by 1024 (or 1000, if you are sure that it is a decimal system of measurement).

X × GB 1024 MB = Y

If we assume too lazy, just use any online converter.