Hexadecimal to Decimal Conversion Guide

Understanding Hexadecimal

Hexadecimal (base 16) uses sixteen symbols: 0–9 for values zero through nine, and A–F for ten through fifteen. Each position represents a power of 16, just as decimal uses powers of 10. Hex is the standard human-readable format for binary data in computing.

Positional Notation Formula

For hex string Hₙ…H₁H₀ (reading left to right):

Decimal = Hₙ×16ⁿ + … + H₁×16¹ + H₀×16⁰

Convert letter digits: A=10, B=11, C=12, D=13, E=14, F=15.

Example 1: A₁₆ to Decimal

A = 10. Result: 10.

Example 2: FF₁₆ to Decimal

F×16¹ + F×16⁰ = 15×16 + 15 = 240 + 15 = 255.

Example 3: 2A₁₆ to Decimal

2×16 + 10 = 32 + 10 = 42.

Example 4: DEAD₁₆ (four-digit hex)

D×16³ + E×16² + A×16 + D = 13×4096 + 14×256 + 10×16 + 13 = 57005.

Alternative: Convert via Binary

Convert each hex digit to 4 bits, concatenate, then interpret as binary positional value. Useful when you think in bits. See Binary to Hexadecimal Guide.

Where Hex Appears

• HTML/CSS colour codes (#FFFFFF white)
• Unicode code points (U+0041 = ‘A’)
• IPv6 addresses (128 bits in hex groups)
• Error codes and status bytes in protocols

Free Tools

Use the Number System Converter with hex input, or look up byte values in the Hexadecimal Table.

Common Mistakes

• Treating A–F as decimal digits (A is 10, not “1”)
• Wrong power direction (leftmost digit is highest power)
• Case sensitivity confusion (a and A are equivalent)

Frequently Asked Questions

What is 0x prefix?

0x is a common programming prefix meaning “the following digits are hexadecimal.” 0xFF = FF hex = 255 decimal.

How do I convert decimal back to hex?

Repeatedly divide by 16; map remainders 10–15 to A–F. See Decimal to Binary Guide — same logic, different base.

Is hex the same as base 16?

Yes. Hexadecimal is base 16 positional notation.

What decimal value fits in two hex digits?

00 to FF = 0 to 255 (one byte).

Does Numverto show conversion steps?

Yes — the Number System Converter displays step-by-step working for hex input.