Why did you make this?

Boredom, mostly. However, to make myself feel better, it does supports very large numbers for conversions and fractions, unlike the standard php functions. An example of a fraction: 1001.1101 (binary), or AB.CD (hex).

What is binary?

"The binary or base-two numeral system is a system for representing numbers in which a radix of two is used; that is, each digit in a binary numeral may have either of two different values. Typically, the symbols 0 and 1 are used to represent binary numbers. Owing to its relatively straightforward implementation in electronic circuitry, the binary system is used internally by virtually all modern computers."

More information on binary..

What is hexadecimal?

"In mathematics, hexadecimal or simply hex is a numeral system with a radix or base of 16 usually written using the symbols 09 and AF or af.

For example, the decimal numeral 79 whose binary representation is 01001111 can be written as 4F in hexadecimal (4 = 0100, F = 1111).

It is a useful system in computers because there is an easy mapping from four bits to a single hex digit. A byte can be represented as two consecutive hexadecimal digits. However, this mixed representation (arabic digits up to nine and for zero, other symbols for the six other hexadecimal digits) is ambiguous and needs prefix, suffix or subscripts to be clear."

More information on hexadecimal..