Hexadecimal (hex) is base 16 — a number system using 16 symbols: digits 0–9 and letters A–F, where A=10, B=11, C=12, D=13, E=14, F=15. It is compact: two hex digits represent exactly one byte (8 bits), making it the standard for expressing memory addresses, colour codes, and binary data in human-readable form.

How do you convert hexadecimal to decimal?

Multiply each hex digit by its power of 16 and sum the results. Example: 0x1A = 1×16 + 10×1 = 16 + 10 = 26₁₀ Place values from right: 16^0=1, 16^1=16, 16^2=256, 16^3=4096... Letters: A=10, B=11, C=12, D=13, E=14, F=15.

How do hex colours work in CSS?

CSS colours use 3 pairs of hex digits, one pair per colour channel: #RRGGBB. Each pair is 00–FF (0–255 decimal): #FF0000 = rgb(255,0,0) = red #00FF00 = rgb(0,255,0) = green #0000FF = rgb(0,0,255) = blue #FFFFFF = rgb(255,255,255) = white #000000 = rgb(0,0,0) = black #808080 = rgb(128,128,128) = mid grey The 3-digit shorthand (#RGB) expands each digit: #F0A = #FF00AA.

Why do programmers use hex?

Three reasons: 1. Compact: 2 hex digits = 1 byte. A 32-bit value fits in 8 hex digits (FFFFFFFF) vs 32 binary digits. 2. Easy binary conversion: each hex digit maps to exactly 4 binary bits (a nibble), making mental conversion straightforward. 3. Standard: memory addresses, error codes, colour values, network packets, and file formats all use hex by convention.

What is the 0x prefix?

The prefix 0x indicates that a number is hexadecimal in most programming languages (C, C++, Java, Python, JavaScript, etc.): 0xFF = 255 in Python, C, JavaScript 0x1A = 26 0xDEAD = 57005 Other notations used: FF₁₆ (mathematics), #FF (CSS colours), FFh (assembly language). This calculator accepts the digits and letters — type without the 0x prefix.

Hex Mega — Convert Any Hexadecimal Number Instantly

The Hex Mega Calculator converts any hexadecimal number (base 16) to decimal, binary, and octal instantly. Enter any hex value using digits 0–9 and letters A–F — letter input is supported and auto-uppercased. The result includes a nibble visualiser showing each hex digit as a coloured tile, place va...

ENTER HEX NUMBER

HEX (digits 0–9 and letters A–F)

0x

QUICK EXAMPLES

CONVERSIONS

DECIMAL (base 10)

255

BINARY (base 2)

11111111₂

OCTAL (base 8)

377₈

PLACE VALUE BREAKDOWN

15 × 16 (16^1) + 15 × 1 (16^0) = 255

CSS GREYSCALE #FFFFFF

#FFFFFF = rgb(255,255,255)

NIBBLE VISUALISER (2 hex digits)

F

F

HEX DIGIT TABLE

BASE CONVERSION SUMMARY

Hex (16)0xFF

Decimal (10)255₁₀

Binary (2)11111111₂

Octal (8)377₈

HEX QUICK REFERENCE

F₁₆ = 15₁₀Max single hex digit

10₁₆ = 16₁₀16 decimal = 10 hex

FF₁₆ = 255₁₀Max 1 byte

100₁₆ = 256₁₀= 2^8

FFFF = 65535₁₀Max 2-byte value

1 hex digit = 4 bitsOne nibble

2 hex digits = 1 byte8 bits

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HOW TO USE

1
Type any hex value using digits 0–9 or letters A through F (upper or lower case — both work, they auto-uppercase). The 0x prefix is shown automatically. Any invalid character is silently blocked.
2
Results appear instantly: decimal in green, binary in red, octal in blue. For large values, binary is shown with a word-break so it doesn't overflow.
3
The nibble visualiser on the right shows each hex digit as a large tile on a black background — numerals in green, letters (A–F) in gold. Below each tile is its decimal equivalent (A=10, B=11... F=15).
4
For values up to 0xFF (255), a greyscale colour swatch shows the CSS colour. For values up to 0xFFFFFF, a full RGB colour chip is shown — making hex colours immediately visual and tangible.

WORKED EXAMPLE

Convert 0xFF to decimal, binary, and octal: F = 15, F = 15 FF₁₆ = 15×16 + 15×1 = 240 + 15 = 255₁₀ 255₁₀ = 11111111₂ = 377₈ So 0xFF = 255₁₀ = 11111111₂ = 377₈ This is the maximum value of one byte (8 bits). In CSS: #FFFFFF = rgb(255,255,255) = white. In CSS: #000000 = rgb(0,0,0) = black.

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Last updated: April 29, 2026 · Verified by EagleCalculator team

Hex Mega — Convert Any Hexadecimal Number Instantly

ENTER HEX NUMBER

HOW TO USE

WORKED EXAMPLE

FREQUENTLY ASKED QUESTIONS

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