Number Base Converter
Free online number base converter. Convert numbers between binary, octal, decimal, hexadecimal, and any custom base instantly. Includes bit visualization and step-by-step conversion explanation.
How to Use the Number Base Converter
Type or paste a number into any field — binary, octal, decimal, hexadecimal, or the custom base — and all other fields update instantly. Click individual bits in the visualization to toggle them and see how each bit position affects the value. Expand the step-by-step explanation to see the full conversion working. Use the 0–255 reference table to look up common values quickly, or click any table row to load it into the converter.
About This Tool
A number base (radix) converter with four primary bases shown simultaneously plus a configurable custom base. All fields are live — editing any one instantly updates all others. Uses BigInt arithmetic for arbitrary-precision conversions. The interactive bit visualization shows the binary representation as clickable bit cells grouped into nibbles with hex labels, making it easy to understand how individual bits affect the value. A step-by-step explanation section shows the full division or positional-weight calculation for five conversion directions. Zero external libraries — everything runs in your browser. Related: Hash Generator for computing cryptographic hashes, URL Encoder for encoding data in URLs.
Quick Reference Table
| Base | Name | Digits | Common Use |
|---|---|---|---|
| 2 | Binary | 0, 1 | Bit flags, bitmasks, low-level programming |
| 8 | Octal | 0–7 | Unix file permissions, legacy systems |
| 10 | Decimal | 0–9 | Everyday numbers, math, finance |
| 16 | Hexadecimal | 0–9, A–F | Memory addresses, colors, byte values |
| 32 | Base 32 | 0–9, A–V | Compact encoding, Crockford identifiers |
| 36 | Base 36 | 0–9, A–Z | Short unique IDs, URL-safe encodings |
Frequently Asked Questions
How do I convert binary to hexadecimal quickly?
Group the binary digits into sets of four from the right, padding with leading zeros. Each group maps to one hex digit: 0000=0, 0001=1, … 1010=A, 1011=B, 1100=C, 1101=D, 1110=E, 1111=F. For example, 10110100 splits into 1011 and 0100, giving 0xB4.
What is a nibble?
A nibble is 4 bits — half a byte. It is the exact amount of information represented by a single hexadecimal digit, which is why hex and binary convert so cleanly.
Why does hexadecimal use letters?
Hex needs 16 unique symbols. After digits 0–9, the letters A through F represent values 10 through 15. Both uppercase and lowercase are valid.
What does two’s complement mean?
Two’s complement is how computers represent negative integers. The most significant bit acts as a sign bit. To find the negative of a number, invert all bits and add 1. For example, -1 in 8-bit two’s complement is 11111111 (255 unsigned).
Is my data sent to a server?
No. All conversions happen entirely in your browser using native BigInt arithmetic. Your data never leaves your device.