Number Base Converter

Convert numbers between binary, octal, decimal, hex, and custom bases

Source Base

or custom:

Number (base 10)

What is a Number Base Converter?

A number base converter transforms numbers between different positional numeral systems — most commonly binary (base 2), octal (base 8), decimal (base 10), and hexadecimal (base 16) — and also supports custom bases from 2 to 36.

How to Use This Number Base Converter

Select the source base using the preset buttons or enter a custom base (2–36)
Type the number in the input field — digits are validated against the chosen base
Conversions to all standard bases appear instantly below
Copy any result using the copy button on the right

Common Use Cases

Converting between hex and binary for low-level programming and debugging
Translating color codes between hex and decimal for CSS and graphics
Working with permissions and bitmasks expressed in octal (e.g. Unix file modes)
Converting numbers for educational purposes when learning about numeral systems

Frequently Asked Questions

What is the highest base supported?

This converter supports bases from 2 to 36. Base 36 uses digits 0–9 and letters a–z. Beyond that, there is no standard character representation for digits.

Why are digits grouped with spaces?

Grouping makes long numbers easier to read. Binary is grouped in 4-bit nibbles, decimal in groups of 3, and hexadecimal in byte pairs (2 hex digits). This aligns with common conventions in computing and matches how these numbers are typically written.

Does this support negative or fractional numbers?

This converter currently handles non-negative integers only. Fractional numbers and negative values require different conversion algorithms and are not supported in this tool.