Number base converter

Convert a whole number between binary, octal, decimal and hexadecimal bases.

Representations are shown without base prefixes; the minus sign is preserved except for zero.

Method and assumptions

Method version 1.0.0 · Updated October 5, 2026

Convert a number

Formula: Value = sum of each digit × base^position, with an optional sign.

Shows the same whole-number value in binary, octal, decimal and hexadecimal. Prefixes such as 0b, 0o and 0x are not required; negative numbers are supported.

value: Number to convert
base: Input number base

Signed whole numbers from 1 to 256 digits in bases 2, 8, 10 or 16. Digits must belong to the selected base.

Calculate with code

These short examples use the same inputs and core calculation as this tool. Adapt validation and formatting to your application.

JavaScript

const value = 45n;
console.log(value.toString(2), value.toString(8), value.toString(16).toUpperCase()); // 101101 55 2D

TypeScript

const value: bigint = 45n;
console.log(value.toString(2), value.toString(8), value.toString(16).toUpperCase()); // 101101 55 2D

Python

value = 45
print(format(value, 'b'), format(value, 'o'), format(value, 'X'))  # 101101 55 2D

Java

long value = 45;
System.out.printf("%s %s %X%n", Long.toBinaryString(value), Long.toOctalString(value), value); // 101101 55 2D

int value = 45;
Console.WriteLine($"{Convert.ToString(value, 2)} {Convert.ToString(value, 8)} {value:X}"); // 101101 55 2D

More languages

#include <stdio.h>
int main(void) { int value = 45; printf("%o %X\n", value, value); } // 55 2D; use repeated division for binary

C++

#include <bitset>
#include <iostream>
int main() { int value = 45; std::cout << std::bitset<8>(value) << " " << std::oct << value << " " << std::hex << value; } // 00101101 55 2d

PHP

$value = 45;
echo decbin($value), ' ', decoct($value), ' ', strtoupper(dechex($value)); // 101101 55 2D

PowerShell

$value = 45
'{0} {1} {2:X}' -f [Convert]::ToString($value, 2), [Convert]::ToString($value, 8), $value # 101101 55 2D