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Number base converter

Convert numbers between binary, octal, decimal, and hexadecimal instantly. Supports arbitrarily large numbers with BigInt precision.

Valid digits: 0-9

Binary (2)
binary (2)
Enter a number above
Octal (8)
octal (8)
Enter a number above
Decimal (10) (input)
decimal (10)
Enter a number above
Hexadecimal (16)
hexadecimal (16)
Enter a number above

What is Number Base Converter?

A number base converter is a tool that translates numbers between different numeral systems — binary (base 2), octal (base 8), decimal (base 10), and hexadecimal (base 16). These number systems are fundamental in computing and programming. Binary is the language computers use internally, representing data as sequences of 0s and 1s. Octal was historically used in Unix file permissions and some older systems. Decimal is the standard human-readable number system. Hexadecimal is widely used in programming for memory addresses, color codes (#FF5733), MAC addresses, and any context where compact binary representation matters. This tool converts between all four bases simultaneously — enter a number in any base and instantly see its representation in the other three. It supports arbitrarily large numbers using JavaScript BigInt, meaning you can convert values well beyond the 53-bit integer limit (9,007,199,254,740,991) that standard number types impose. The bit visualization feature displays binary output in grouped nibbles (4-bit groups) with bit position labels, making it easy to inspect individual bits for debugging, bitwise operations, or learning digital logic. Everything runs in your browser with zero server calls.

How to Use Number Base Converter

  1. 1

    Select your input base

    Click one of the four base buttons — Binary (2), Octal (8), Decimal (10), or Hexadecimal (16) — to tell the tool what format your number is in. The input field will only accept valid digits for the selected base.

  2. 2

    Enter your number

    Type or paste your number into the input field. The tool validates each character in real time and shows an error if you enter an invalid digit for the selected base. Conversions to all four bases appear instantly below as you type.

  3. 3

    Copy or inspect the results

    Click the Copy button next to any conversion result to copy it to your clipboard. For binary output, scroll down to the bit visualization to see individual bits grouped into nibbles with position labels — useful for understanding bitwise operations and data structures.

Features

  • Simultaneous conversion to binary, octal, decimal, and hexadecimal from any input base
  • Real-time conversion that updates instantly as you type each character
  • BigInt support for numbers beyond the 53-bit JavaScript integer limit
  • Input validation that only accepts valid digits for the selected base
  • Visual bit display with 4-bit nibble grouping and bit position labels
  • One-click copy button on every conversion result
  • Zero server calls — all conversion runs entirely in your browser
  • Clean prefix display (0b, 0o, 0x) for easy identification of number bases

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Frequently Asked Questions

How do I convert binary to decimal?+
Select Binary (2) as the input base, then type your binary number (using only 0s and 1s) into the input field. The decimal equivalent appears instantly in the Decimal (10) output row. For example, entering 11010 in binary shows 26 in decimal.
What is the largest number this tool can convert?+
This tool uses JavaScript BigInt internally, so there is no practical upper limit. You can convert numbers with hundreds or even thousands of digits. Standard JavaScript numbers are limited to 53 bits (about 9 quadrillion), but BigInt removes that constraint entirely.
Why is hexadecimal important in programming?+
Hexadecimal is a compact way to represent binary data — each hex digit maps to exactly 4 binary bits. This makes it ideal for memory addresses, CSS color codes (#FF5733), byte values (0x00 to 0xFF), MAC addresses, and debugging. It is far more readable than long binary strings.
What are the valid digits for each base?+
Binary (base 2) uses 0 and 1. Octal (base 8) uses 0 through 7. Decimal (base 10) uses 0 through 9. Hexadecimal (base 16) uses 0 through 9 and A through F (case-insensitive). The tool enforces these rules automatically and rejects invalid characters.
What is the bit visualization showing?+
The bit visualization displays the binary representation of your number with individual bits shown as cells, grouped into nibbles (4-bit groups). Each group is labeled with its bit position range (e.g., 7-4, 3-0). Bits that are 1 are highlighted in amber, making it easy to see which bits are set — useful for understanding bitwise operations, flags, and data encoding.
Can I convert negative numbers or floating-point numbers?+
This tool handles non-negative whole numbers. Negative numbers and floating-point decimals are not supported because their binary representations depend on the encoding scheme (twos complement, IEEE 754, etc.), which varies by context. For signed integers, you can manually apply twos complement to the binary output.