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Hex to Decimal Converter

Convert hexadecimal to decimal. Perfect for color codes, memory addresses, and debugging register values.

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ASCII Letter A

Convert the ASCII code for uppercase A (65) across all bases.

Key values: Decimal 65 · Binary 1000001 · Hex 41

Byte Maximum

The largest value a single byte can hold (255).

Key values: Decimal 255 · Binary 11111111 · Hex FF

Hex Color Code

Convert a common hex color code (deep sky blue) to other bases.

Key values: Hex 00BFFF · Decimal 49151 · Binary nibbles

Convert a Number

Enter a number in any base to see it converted to binary, octal, decimal, hexadecimal, and any custom base 2-36.

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The Hexadecimal System

Hexadecimal (base-16) uses sixteen digits: 0–9 for values 0–9 and A–F for values 10–15:

Hex	0	1	2	3	4	5	6	7	8	9	A	B	C	D	E	F
Dec	0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15

Hex is case-insensitive: 3F and 3f are the same value.

Conversion Method

Multiply each hex digit by its positional power of 16 and sum:

(h_n h_{n-1} \ldots h_1 h_0)_{16} = \sum_{i=0}^{n} h_i \times 16^i

Worked Example

Convert $\text{2AF}_{16}$ to decimal:

2 \times 16^2 + 10 \times 16^1 + 15 \times 16^0 = 512 + 160 + 15 = 687

Hex in Web Colors

CSS colors use hex notation: #RRGGBB, where each pair is a hex value from 00 (0) to FF (255):

Color	Hex	RGB Decimal
Red	`#FF0000`	(255, 0, 0)
Green	`#00FF00`	(0, 255, 0)
Blue	`#0000FF`	(0, 0, 255)
White	`#FFFFFF`	(255, 255, 255)
Steel Blue	`#4682B4`	(70, 130, 180)

Why hex for colors? Each RGB channel is one byte (0–255), which maps perfectly to two hex digits (00–FF). This makes hex the most compact human-readable notation for 24-bit color values.

Hex Notation Conventions

0x prefix — C, C++, JavaScript, Python: 0x2AF
# prefix — CSS colors: #2AF or #0022AAFF
$ prefix — Assembly, Pascal: $2AF
h suffix — Intel assembly: 2AFh
U+ prefix — Unicode code points: U+0041 (letter A)

Frequently Asked Questions

How do you convert hexadecimal to decimal?

Multiply each hex digit by its positional power of 16 and sum. For hex digits A–F, use their decimal values 10–15. For example, $\text{2AF} = 2 \times 16^2 + 10 \times 16^1 + 15 \times 16^0 = 512 + 160 + 15 = 687$ .

Is hexadecimal case-sensitive?

No. Both uppercase (A–F) and lowercase (a–f) represent the same values. Convention is to use uppercase in output, but inputs are accepted in either case.

Why is hex used for CSS color codes?

Each RGB color channel is one byte (0–255), which maps perfectly to two hex digits (00–FF). This makes hex the most compact human-readable notation for 24-bit color values. For example, #FF5733 means R=255, G=87, B=51.

What does the 0x prefix mean before hex numbers?

The 0x prefix is a programming convention used in C, JavaScript, Python, and many other languages to indicate that the following digits are hexadecimal, not decimal. Other conventions include # (CSS), $ (assembly), and U+ (Unicode).

What is the decimal value of FF in hex?

FF in hex equals $15 \times 16 + 15 = 255$ in decimal. This is the maximum value of a single byte (8 bits all set to 1), which is why it appears as the maximum for each RGB color channel.

Hex to Decimal Converter

Convert hexadecimal to decimal. Perfect for color codes, memory addresses, and debugging register values.

Try an Example

ASCII Letter A

Byte Maximum

Hex Color Code

Convert a Number

Related conversion Variants

Binary to Decimal

Decimal to Binary

Decimal to Hex

Binary to Hex

Octal to Decimal

More Math Calculators

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Try an Example

ASCII Letter A

Byte Maximum

Hex Color Code

Convert a Number

The Hexadecimal System

Conversion Method

Worked Example

Hex in Web Colors

Hex Notation Conventions

Frequently Asked Questions

How do you convert hexadecimal to decimal?

Is hexadecimal case-sensitive?

Why is hex used for CSS color codes?

What does the 0x prefix mean before hex numbers?

What is the decimal value of FF in hex?