Hexadecimal Explained: What is Hex and How to Convert It

What is Hexadecimal?

Hexadecimal (hex) is a base-16 number system. While decimal uses digits 0–9 and binary uses 0–1, hex uses 16 symbols: digits 0–9 plus letters A–F (where A=10, B=11, C=12, D=13, E=14, F=15). A single hex digit can represent values from 0 to 15.

Why Do Computers Use Hex?

Computers store everything in binary, which can become very long very quickly. Hex is a compact shorthand: one hex digit represents exactly 4 binary bits (a "nibble"), and two hex digits represent one byte (8 bits). This makes hex much easier to read and write than binary while still mapping cleanly to how computers store data.

Hex to Decimal Conversion

Each position represents a power of 16. To convert hex to decimal, multiply each digit by 16 to the power of its position.

Example: 2F in hex

• 2 × 16^1 = 32
• F (=15) × 16^0 = 15
• Total: 32 + 15 = 47 in decimal

Common Hex Values

• 0xFF = 255 (max value of one byte)
• 0x10 = 16
• 0x1A = 26
• 0x64 = 100
• 0xFFFFFF = 16,777,215 (used in RGB color codes)

Where You'll See Hex in Real Life

• Colors in web design: #FF5733, #1E90FF are hex RGB values
• Memory addresses in programming and debugging
• MAC addresses on network devices (e.g. A1:B2:C3:D4:E5:F6)
• File formats and encodings in low-level programming

Convert hex to decimal, binary or octal instantly with our free number system converter.

Step-by-Step Conversion Examples

Decoding a Web Color: #3B82F6

The CSS color #3B82F6 (a shade of blue used widely in UI design) breaks down as three hex pairs — one per RGB channel:

• 3B (red): 3×16 + 11 = 48 + 11 = 59 out of 255
• 82 (green): 8×16 + 2 = 128 + 2 = 130 out of 255
• F6 (blue): 15×16 + 6 = 240 + 6 = 246 out of 255

So #3B82F6 = RGB(59, 130, 246) — a strong blue with low red, moderate green, and high blue. There are exactly 16,777,216 possible web colors (256³), corresponding to six hex digits (two per channel). #FFFFFF = white (255,255,255); #000000 = black; #FF0000 = pure red.

Reading a Memory Address in a Debugger

A crash report shows address 0x00007FFE4A3C. The hex prefix tells a systems programmer the memory region instantly:

• Addresses 0x0000_0000 to 0x7FFF_FFFF → user space (below 2 GB boundary)
• Addresses 0xFFFF_8000_0000_0000 and above → kernel space (64-bit Linux)
• 0x7FFE = 32,766 decimal — confirming this address is in user space

In 64-bit Windows processes, user-mode addresses stay below 0x7FFF_FFFF_FFFF. Reading hex directly makes these region boundaries visible — 0x80000000 = exactly 2 GiB = the classic 32-bit user/kernel boundary — in a way that decimal (2,147,483,648) does not.

Converting Hex to Binary Directly

Every hex digit maps to exactly 4 binary bits (a nibble), making the conversion table worth memorizing:

• 0 = 0000   1 = 0001   2 = 0010   3 = 0011
• 4 = 0100   5 = 0101   6 = 0110   7 = 0111
• 8 = 1000   9 = 1001   A = 1010   B = 1011
• C = 1100   D = 1101   E = 1110   F = 1111

Converting 0xDEAD to binary: D=1101, E=1110, A=1010, D=1101 → 1101 1110 1010 1101. To decimal: 8192+4096+2048+1024+512+256+128+32+8+4+1 = 57,005. The 0xDEAD value famously appears in embedded systems debugging as a sentinel value for uninitialized memory. 0xBEEF, 0xCAFE, and 0xFACE are similar mnemonics used as magic numbers.

Hex in Security and Networking

A MAC address identifies a network interface uniquely worldwide. The address A1:B2:C3:D4:E5:F6 translates as:

• First 3 bytes (OUI — Organizationally Unique Identifier): A1:B2:C3 — identifies the hardware manufacturer
• Last 3 bytes: D4:E5:F6 — device-specific identifier assigned by the manufacturer

SHA-256 cryptographic hashes are 64 hex characters = 256 bits = 32 bytes. Git commit hashes are 40 hex characters (SHA-1 = 160 bits). UUID v4 identifiers follow the pattern xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx — all hex digits — providing 122 bits of randomness (approximately 5.3×10³⁶ unique values). Every time you install a package, clone a repo, or send a secure HTTPS request, you're working with hexadecimal behind the scenes.

Source: IEEE 802 MAC address standard; W3C CSS Color Level 4 specification. Last verified: May 2026.