Hexadecimal

What hex is

Hexadecimal (hex) is base 16 — a human-friendly shorthand for binary.

Denary	Binary	Hex
10	1010	A
11	1011	B
12	1100	C
13	1101	D
14	1110	E
15	1111	F

The key idea

One hex digit = exactly 4 bits (one nibble). One byte = two hex digits.

Binary → hex

Split into nibbles, convert each:

1111 1010  →  F   A   →  FA

Hex → binary

Convert each digit to 4 bits:

2 D  →  0010 1101

Hex → denary

Multiply the first digit by 16, add the second.

2D = (2 × 16) + 13 = 45

Why it's used

• Shorter and less error-prone than long binary strings.
• Colour codes (#FF0000 = red), memory addresses, MAC addresses.

Exam tip

Memorise A=10 … F=15. Most hex questions are two separate nibble conversions joined together.