Hex Calculator
Convert numbers between decimal and hexadecimal in either direction.
Try an example
FF
About this calculator
How This Hex Calculator Works
Choose a direction — decimal to hexadecimal, or hexadecimal to decimal — enter a value, and the calculator converts it instantly.
Worked Example
255 in decimal converts to FF in hexadecimal — the maximum value representable in 2 hex digits, matching one byte.
Why Hexadecimal Uses Letters
Hexadecimal is base 16, which needs 16 distinct single-character digits. After 0 through 9 are used up, the letters A through F stand in for the values 10 through 15 — so a single hex digit can represent any value from 0 to 15.
Where Hex Shows Up
- Color codes — web and design colors are commonly written as hex (like #FF5733), where each pair of digits represents red, green, and blue intensity
- Memory addresses and debugging — hex is the standard way to display raw memory locations and low-level data
- MAC addresses — network hardware identifiers are written in hex pairs
Hex is popular for these uses because each hex digit maps to exactly 4 binary digits, making it a compact, human-readable stand-in for binary data — see the Binary Calculator for the base-2 equivalent.
Worked example
255 in decimal converts to FF in hexadecimal — the maximum value representable in 2 hex digits (matching one byte).
Frequently asked questions
Where is hexadecimal commonly used?
Color codes in web design and design tools (like #FF5733), memory addresses, MAC addresses, and error codes are all commonly shown in hex, since it's a compact way to represent binary data.
How do I do hex arithmetic (addition, subtraction)?
Convert each hex number to decimal, perform the arithmetic in decimal, then convert the result back to hex using this calculator.
Why does hex use letters A-F?
Hexadecimal is base 16, which needs 16 distinct digits — after 0-9 are used up, the letters A through F represent the values 10 through 15.