Dev & Computing · 十六进制（Hexadecimal） · Updated 2026-10-25
What Is Hexadecimal?
Definition
Hexadecimal uses 16 symbols (0-9, A-F); each digit maps to 4 bits (a nibble), so two hex digits represent exactly one byte. Color codes like #FF5733, memory addresses, MAC addresses and MD5 digests all use hex — not because it is "fancier" but because conversion between human-friendly decimal and machine binary is most direct: FF = 255.
Formula
Hex → decimal: sum each digit × 16ⁿ; FF = 15×16 + 15 = 255
Worked Example
In the color #FF5733: FF = red 255, 57 = green 87, 33 = blue 51 — identical to RGB(255,87,51). The IPv4 address 192.168.1.1 in hex is C0.A8.01.01.
Common Misconception
Assuming hex "makes numbers bigger" — it is only a numeral system: decimal 255 and hex FF are the same value. Case is irrelevant in HTML (#ff5733 equals #FF5733), but digit count is not: FF is two digits, not one.
Matching Calculators
Related Terms
Keep Exploring
Browse the full glossary, or head back to the homepage for 1,435 free online calculators.
Back to glossary