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Encoders, converters & dev utilities
Hex to Decimal Converter — with Step-by-Step Working
Convert a hexadecimal number like FF to decimal and see the working. Hex is base-16, so each digit is worth a power of 16 and the letters A–F stand for 10–15. The decimal value is the sum of each digit times its place value. Worked example: FF₁₆ = 15·16 + 15·1 = 240 + 15 = 255₁₀. A single A is just 10: A₁₆ = 10·1 = 10₁₀ (and equals 1010₂). Hex is everywhere in computing — color codes, memory addresses, byte dumps — because two hex digits map exactly to one byte. This tool shows all four bases at once, uses BigInt for large values, and runs 100% in your browser. Free, no login.
Hex → decimal = Σ (digit × 16^position), with A–F meaning 10–15 (positional notation, base 16)
- Byte-exact worked example: FF₁₆ = 15·16 + 15·1 = 240 + 15 = 255₁₀
- Single digit: A₁₆ = 10₁₀ (and A₁₆ = 1010₂ = 12₈)
- Two hex digits = exactly one byte (00–FF = 0–255), which is why hex is used for colors and byte dumps
- Large inputs use BigInt (no float error); runs 100% client-side
Frequently asked questions
How do I convert hex to decimal?
Treat the number as base-16: each digit has a place value that is a power of 16 (…256, 16, 1) and the letters A–F represent 10–15. Multiply each digit by its place value and add. For FF: F is 15, so 15·16 + 15·1 = 240 + 15 = 255. The tool shows that working and also the binary and octal forms.
What is FF in hex as a decimal?
FF is 255. Both digits are F (15), so 15·16 + 15 = 240 + 15 = 255. That is the maximum value of a single byte, which is why FF appears constantly — a color channel of #FF is fully on, and a byte of 0xFF is all bits set (11111111 in binary).
Why is hexadecimal used so much in computing?
Because it lines up cleanly with bytes. Each hex digit encodes exactly four bits (a nibble), so two hex digits are precisely one 8-bit byte (00 to FF = 0 to 255). That makes hex a compact, readable way to write binary data — memory addresses, color codes like #FF8800, and hex dumps all use it because the mapping to bits is exact and easy.