DIGITAL INFORMATION BIT and BYTE CONVERSION CALCULATOR
Units of Digital Information in Computing and Telecommunications
Definition:
bit (bit, b)
A bit is the basic unit of information in computing and telecommunications; it is the amount of information that can be stored by a device and can normally exist in only two distinct states. A bit can also be defined as a variable or computed quantity that can have only two possible values. These two values are often interpreted as binary digits and are usually denoted by digits 0 and 1. ISO/IEC IEC 80000-13:2008 specifies that the symbol for bit should be "bit", though the letter "b" (in lower case) is still widely used.
byte (B) also octet(o)
A byte or octet is a unit of memory or data equal to the amount used to represent one character; The size of a byte is typically hardware dependent, but the modern de facto standard is 8 bits. However, byte has been used for numbers of bits other than 8. To avoid the risk of confusion ISO/IEC IEC 80000-13:2008 strongly recommends that the name byte and the symbol "B" (capital letter) be used only for 8-bit bytes. A computer with 8-bit bytes can distinguish 28 = 256 different characters. The symbol "B" is not international and should not be confused with the symbol "B" for bel
Prefixes for binary multiples
Computers use bits (binary digit), which are composed of ones and zeros. The decimal number system in contrast has ten unique digits, zero through nine. But although computer data and file size is normally measured using the binary number system (counted by factors of two 1, 2, 4, 8, 16, 32, 64, etc), the prefixes for the multiples were based on the metric/SI system because computer industry noticed that 210 was very nearly equal to 1000 and started using the SI prefix "kilo" to mean 1024! So, although a metric/SI "kilo" equals 1,000 (e.g. one kilogram = 1,000 grams), a binary "Kilo" equals 1,024 (e.g. one Kilobyte = 1,024 bytes). Not surprisingly leading to confusion, particularly when many storage device manufacturers and telecommunications engineers use the decimal prefixes. So a "500 GB hard drive" may show only 465 GB (500,000,000,000 bytes) on the computer. No Surprise, some may feel they have been cheated out of 35 GB. A big potential for confusion and for incompatibility in standards and in implemented systems exists.
In December 1998, the International Electrotechnical Commission (IEC) approved a new standard. Instead of using the metric prefixes for multiples in binary code, the new IEC standard called for specific prefixes for binary multiples made up of only the first two letters of the metric prefixes and adding the first two letters of the word "binary". Instead of Kilobyte (KB) or Gigabyte (GB), the new terms would be kibibyte (KiB) or gibibyte (GiB).
Summary
The common use of metric/SI prefixes for binary multiples can lead to confusion over whether value is binary or decimal. Use of "k" for decimal kilo and "K" for binary helps but not with other prefixes like mega (M) and giga (G). Symbol b for bit and B for byte is used to differentiate, but is still subject to confusion.
New IEC standard should make things clearer. Confusion may still exist with use of old and new metric/SI prefixes.
KiB - kibibyte - 1024 (210) bytes
MB - megabyte - 1000000 (106) bytes. (SI prefix for decimal use only - may cause confusion with old system).
Symbol
Prefix
SI
Binary
Size difference
k
kilo
103 = 10001
210 = 10241
2.40%
M
mega
106 = 10002
220 = 10242
4.86%
G
giga
109 = 10003
230 = 10243
7.37%
T
tera
1012 = 10004
240 = 10244
9.95%
P
peta
1015 = 10005
250 = 10245
12.59%
E
exa
1018 = 10006
260 = 10246
15.29%
Z
zetta
1021 = 10007
270 = 10247
18.67%
Y
yotta
1024 = 10008
280 = 10248
20.89%
Symbol
Prefix
Ki
kibi, binary kilo
kibibyte (KiB)
210 bytes
1024 B
Mi
mebi, binary mega
mebibyte (MiB)
220 bytes
1024 KiB
Gi
gibi, binary giga
gibibyte (GiB)
230 bytes
1024 MiB
Ti
tebi, binary tera
tebibyte (TiB)
240 bytes
1024 GiB
Pi
pebi, binary peta
pebibyte (PiB)
250 bytes
1024 TiB
Ei
exbi, binary exa
exbibyte (EiB)
260 bytes
1024 PiB
Zi
zebi, binary zetta
zebibyte (ZiB)
270 bytes
1024 EiB
Yi
yobi, binary yotta
yobibyte (EiB)
280 bytes
1024 ZiB
Data Transfer Rate - bits per second and bytes per second are confusing to those outside the specific industries. Terms such as 56K, 56 kb/s, 56Kb/s, 56 kbps, 56 Kbps, 56 kBps, 56 KBps etc. don't help. In most cases bitrate prefixes are used in the decimal sense.
To use the measurement conversion calculators simply enter a number value into the desired field and click calculate. All results shown will be equivalent values. Values are given to seven significant figures ( the odd result may show 9's or 0's over running). Values of 10 000 or greater will be displayed in the e-format e.g. 2.3456e7 which equals 2.3456 x 107 or 23 456 000. Values lower than 0.001 will be displayed in the e-format e.g. 2.3456e-5 which equals 2.3456 x 10-5 or 0.000 023456. The calculators require that your browser has java script enabled. View all measurement unit conversion calculators on the same page (may not work with all browsers; requires Iframe).
