Hex to Decimal Converter
Convert hexadecimal to decimal — base sixteen, where the digits run 0–9 then A–F.
Hexadecimal counts in sixteens, using A to F for the values ten to fifteen.
How the hex to decimal converter works
Hexadecimal counts in sixteens, using A to F for the values ten to fifteen. Each place is worth sixteen times the one to its right, so FF is 15 × 16 + 15 = 255. It exists because one hex digit is exactly four binary digits, so a byte is always two hex characters — which is why colors are written #FF8800 and memory addresses in hex.
Formula: value = Σ digitₖ × bᵏ
Worked examples
| Inputs | Converted | Note |
|---|---|---|
| FF | 255 | 255 — one byte at maximum |
| 1A | 26 | 26 |
| FFFF | 65535 | 65535 |
FAQFrequently asked questions
What do the letters mean?
A=10, B=11, C=12, D=13, E=14, F=15 — the digits past nine.
What is FF in decimal?
255, the largest value one byte can hold.
Why does hex exist?
One hex digit is exactly four bits, so a byte is always two characters — far easier to read than eight ones and zeros.
What does #FF8800 mean?
A color: red 255, green 136, blue 0 — each pair is one byte per channel.
Is 0x important?
It is just a prefix marking a number as hex in most programming languages; the calculator accepts it either way.
Where these figures come from
- NIST Digital Library of Mathematical Functions — reference definitions for elementary and special functions
- Wolfram MathWorld — definitions and formulas for every topic on this page
- NIST/SEMATECH e-Handbook of Statistical Methods — the statistical formulas (mean, variance, z, confidence intervals, sample size)
- Common Core State Standards — Mathematics — the terms and methods taught in US schools
Last checked: September 2026. Formulas are fixed by mathematics and do not change with tax years or regulations.