Number Base Converter (Hex, Dec, Bin, Oct)
Convert numbers between Decimal, Hexadecimal, Binary, and Octal formats instantly in real-time.
Number Systems & Radix Base Conversion Guide
Convert numerical values across standard computing bases used in memory addressing, bitwise operations, and low-level programming.
1. Base 16 (Hexadecimal)
Uses digits 0-9 and characters A-F. Used for memory pointer addresses, RGB color codes, and byte representations.
2. Base 2 (Binary)
Uses bits 0 and 1. Standard fundamental data representation for digital electronics and computer hardware logic.
3. Base 8 (Octal) & Base 10
Octal uses digits 0-7 (used in Unix file permission masks e.g. 755). Decimal is standard base 10 human representation.
About the Number Base Converter
The Number Base Converter shows the same value simultaneously in binary, octal, decimal and hexadecimal. It is the quickest way to read a bitmask from a permissions field, translate a hex colour component or memory offset into decimal, or check how a flag enum lines up in binary. Enter a value in any base and the other representations update immediately.
How to use the Number Base Converter
- Type a value into the field for the base you already have.
- Read the equivalent value in the other three bases.
- Copy whichever representation you need.
Frequently asked questions
Why do hexadecimal values start with 0x?
The 0x prefix is a convention from C that tells a compiler or reader the digits that follow are base 16 rather than base 10. Similar prefixes exist for binary (0b) and octal (0o). The prefix is notation only and is not part of the value.
How large a number can I convert?
Values are handled with arbitrary-precision integer arithmetic, so conversions remain exact well beyond the 2^53 limit of a standard JavaScript number. Fractional values are not supported.
Why is hexadecimal used for colours and memory addresses?
Each hex digit maps to exactly four bits, so one byte is always two hex digits. That makes byte boundaries visible at a glance, which is far more readable than the long digit strings decimal produces for the same value.
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Number Base Converter is free to use with no account, no ads and no usage limits. Every calculation runs locally in your browser, so nothing you paste is ever uploaded. See our privacy policy.