Convert Hexadecimal to Decimal

Convert Hexadecimal (hex) to Decimal (dec) instantly and accurately.

Selected Hexadecimal (hex) - available characters: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F

Conversion Formula

Step-by-step example using the value 42 (decimal):

Convert Hexadecimal (base 16) → Decimal (base 10)

Step 1: Expand each digit of 2A (hex) by position:

        2 × 16^1 = 32
        A × 16^0 = 10
        ────────────
        Sum = 42 (decimal)

Step 2: Target is decimal - Step 1 result is the final answer.

────────────────────────────
Result:  2A (hex) = 42 (dec)

About Hexadecimal

Hexadecimal (base 16) uses digits 0-9 and A-F (A=10, B=11, C=12, D=13, E=14, F=15). Each position is a power of 16: 16⁰=1, 16¹=16, 16²=256. Because 16 = 2⁴, each hex digit = exactly 4 bits (one nibble). Ubiquitous in computing: memory addresses (0x7FFF…), CSS colours (#FF5733), IPv6, SHA-256 hashes (64 hex digits = 256 bits), MAC addresses, UUID/GUIDs, and binary file magic numbers. The '0x' prefix originated in C (1972) and is standard in C++, Java, Python, JS, Rust, and Go. Conversion: decimal 42 = 2×16+10 = 2A₁₆.

About Decimal

Decimal (base 10) is the universal positional system using digits 0-9. Each position is a power of 10: 10⁰=1, 10¹=10, 10²=100. Attributed to human anatomy (ten fingers). The Hindu-Arabic system - including zero - was formalised by Brahmagupta (628 CE) and spread via al-Khwarizmi (c. 820 CE). SI and metric systems are base-10. IEEE 754-2008 added decimal64/128 formats for exact decimal arithmetic in financial applications. Conversion: decimal 42 is the reference value used throughout this converter.

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