Number Base Converter

Convert numbers between any bases from 2 to 36. View binary, octal, decimal, and hexadecimal side by side, with a custom from/to base selector.

About Number Base Converter

Overview

The Number Base Converter is a fast, browser-based tool for converting numbers between any numeral system from base 2 (binary) to base 36. It shows binary, octal, decimal, and hexadecimal representations at the same time, and lets you pick a custom input and output base for any value in between. It is useful for students learning how positional number systems work, for programmers who read memory dumps, network packets, or color codes, and for anyone working with low-level data.

Features

  • Converts any integer between base 2 and base 36.
  • Shows binary, octal, decimal, and hexadecimal at the same time.
  • Custom from base and to base selectors for any value from 2 to 36.
  • Validates each digit against the chosen input base and shows clear errors.
  • Supports negative numbers using a leading minus sign.
  • Handles very large numbers correctly using arbitrary-precision arithmetic.
  • One-click copy buttons on every output.
  • Live mode updates all five representations as you type.
  • All processing happens in your browser, so your data never leaves the device.
  • Includes a dark mode and a responsive layout for mobile through desktop.

How to Use

  1. Type or paste the number you want to convert into the input area.
  2. Pick the base your input is written in (default is decimal, base 10).
  3. Pick the target base for the custom output (default is hexadecimal, base 16).
  4. Turn on live mode to see all five representations update as you type.
  5. Use the CONVERT NUMBER button when live mode is off.
  6. Fix the input if the tool reports an error about illegal digits.
  7. Use the copy button next to any output to copy just that representation.
  8. Click Clear to reset everything to a blank state.

FAQ

What number bases does this tool support?

Any base from 2 to 36 is supported. Base 2 is binary and uses the digits 0 and 1, while base 36 uses the digits 0 through 9 followed by the letters A through Z. Bases outside this range are not supported by the standard digit set used in computing.

What happens if I type a digit that is not allowed in the chosen from base?

The tool stops, leaves the output areas empty, and shows an error message explaining which character was unexpected. For example, the digit F is allowed in base 16 but not in base 10. Remove or correct the offending character and the conversion will resume.

Can I convert negative numbers or very large numbers?

Negative integers are supported when written with a leading minus sign, such as -255. The tool also handles very large integers correctly because it uses arbitrary-precision arithmetic internally, so you will not lose digits on long binary or hexadecimal strings.

Why are the four common bases shown in addition to my custom from and to base?

The four common bases are the ones programmers reach for most often, so the tool displays them together for quick reference. The custom from and to selectors let you also work in any other base from 2 to 36, including unusual ones like base 3 or base 32.