Calculators
Number Base Converter
Convert numbers between binary (base 2), octal (base 8), decimal (base 10) and hexadecimal (base 16), plus any custom base from 2 to 36. Useful for programming, digital electronics and computer science.
About the Number Base Converter
Convert integers between binary (base 2), octal (base 8), decimal (base 10), hexadecimal (base 16), or any custom base from 2 to 36. All four standard bases are shown simultaneously.
Where each base is used
Binary: Machine code, bitwise operations, CPU registers. Octal: Unix file permissions (chmod 755). Hex: Colours (#ff6600), memory addresses, byte values. Hex digits use 0–9 then A–F.
Frequently asked questions
What is hexadecimal used for in computing?
Hexadecimal (base 16) is widely used in programming because each hex digit represents exactly 4 bits, making it compact shorthand for binary. It is used for memory addresses, colour codes (e.g. #FF5500), opcodes and byte values.
What base does JavaScript use internally?
JavaScript's parseInt() function can parse strings in any base from 2–36 and all numbers are stored internally as 64-bit IEEE 754 floating-point (base 2). This converter uses parseInt(value, base).toString(targetBase).