Hex to Decimal Converter
Convert hexadecimal numbers to decimal, with binary and octal equivalents.
Last updated · View algorithm, constants and default inputs (JSON)
About this calculator
Hexadecimal uses sixteen symbols, so each digit carries four bits of information. Memory addresses, colour codes and byte dumps are all written in hex for exactly that reason.
Worked example
calculated with the default values below
Hexadecimal number FF Decimal 255 · Binary 11111111 · Octal 377 · Hex digits 2 · Bytes 1
General background references
Disclaimer
These calculators give general mathematical results. They suit study, planning and estimation — verify anything that feeds a graded submission, a published figure or a financial commitment.
Implementation source
This record describes the implementation used by this page. It is not independent validation. External references, when available, support only the stated formula or definition; estimates and custom rules retain their own assumptions.
Formula and variables
n = Σ d_k×16^k; bytes = ceil(hex_digits/2)
- d_k
- hex digit value (0–15)
- k
- position from the right, starting at 0
- digits
- number of hex digits
Decimal value is parsed exactly within JavaScript’s safe integer range. Hex digits count includes leading zeros; whole-byte capacity = ceil(digits/2).
Frequently asked questions
Why is byte count rounded up for an odd number of hex digits?
Each hex digit is a 4-bit nibble and a stored byte holds 8 bits. The calculator reports whole bytes as the ceiling of digit count divided by two: F needs one byte, and FF needs one byte. Leading zero digits count toward the entered width.
Which hexadecimal input is accepted?
Enter hexadecimal digits (0–9, A–F) with an optional 0x prefix. Other characters, empty input, and integers above JavaScript’s exact integer range are rejected so the decimal result is not silently altered.