Hexadecimal to Decimal Converter
Convert hexadecimal numbers (base 16) to decimal (base 10) with positional power-of-16 math.
How to use it
- Enter hex characters to calculate decimal value.
Examples
| FF | 255 |
| 100 | 256 |
Hexadecimal (base 16) numbers show up constantly in web colors, memory addresses and debugging output — but they need converting to decimal (base 10) to be useful in ordinary arithmetic. Each hex digit is multiplied by a power of 16 based on its position, then the results are summed.
Worked example
FF: F=15 in the 16¹ place and F=15 in the 16⁰ place. (15×16) + (15×1) = 240 + 15 = 255.
100: 1 is in the 16² place, so 1×256 + 0×16 + 0×1 = 256. This is why hex '100' equals decimal 256, not 100 — a common source of confusion for beginners.
Where this comes up
- Reading a hex color code (e.g. #FF5733) and finding the decimal RGB values behind it
- Interpreting memory addresses or error codes reported in hex by an operating system or debugger
- Computer science coursework and technical interview prep on number-base arithmetic
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Last updated 18 August 2026