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The number base converter transforms numbers between different numeral systems. It supports six bases and handles arbitrarily large numbers using JavaScript’s BigInt.

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Features

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Six supported bases

Convert between:
  • Binary (Base 2) - Uses digits 0-1
  • Octal (Base 8) - Uses digits 0-7
  • Decimal (Base 10) - Standard base with digits 0-9
  • Hexadecimal (Base 16) - Uses digits 0-9 and letters A-F
  • Base32 - Uses A-Z and 2-7 (RFC 4648 alphabet)
  • Base64 - Uses A-Z, a-z, 0-9, +, / alphabet

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Large number support

The utility uses BigInt internally, allowing you to convert numbers far beyond JavaScript’s standard number limits without precision loss.

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All representations view

After conversion, see your number in all six bases simultaneously with a convenient table that includes:
  • Base name badges
  • Formatted values with prefixes (0b, 0x, 0o)
  • Individual copy buttons for each representation

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Prefix recognition

The converter automatically strips common prefixes:
  • 0b for binary
  • 0o for octal
  • 0x for hexadecimal
You can enter numbers with or without these prefixes.

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Swap bases

Quickly swap the source and target bases to reverse your conversion direction.

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Built-in examples

Access common conversions:
  • Decimal 255 (maximum byte value)
  • Binary 11111111
  • Hexadecimal FF
  • One million in decimal
  • DEADBEEF (classic hex value)

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Keyboard shortcuts

Work efficiently with shortcuts for:
  • Converting numbers
  • Copying results
  • Clearing fields

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Use cases

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Programming and debugging

Convert memory addresses, bit flags, or color values: 
Input: 255 (decimal)
Output: FF (hex), 11111111 (binary), 377 (octal)

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Network addressing

Convert IP address components or subnet masks between decimal and hexadecimal.

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Color codes

Convert RGB decimal values to hexadecimal for CSS: 
Input: 59 (red channel)
Output: 3B (hex)

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Data encoding

Convert numerical identifiers to Base32 or Base64 for compact representation.

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Learning computer science

Understand how different numeral systems represent the same value.
Base32 and Base64 representations use character alphabets rather than pure numerical notation, making them suitable for encoding in text-based systems.

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How it works

The conversion process:
  1. Input validation - Checks that your input matches the expected character set for the source base
  2. Parse to BigInt - Converts the input to a BigInt decimal value
  3. Convert to target base - Transforms the BigInt to the target base representation
  4. Generate all bases - Computes representations in all six bases for the reference table
Standard bases (2, 8, 10, 16):
  • Uses JavaScript’s built-in toString(radix) method
  • Hexadecimal output is uppercase
Base32:
  • Uses RFC 4648 alphabet: ABCDEFGHIJKLMNOPQRSTUVWXYZ234567
  • Converts by repeatedly dividing by 32
Base64:
  • Uses standard alphabet: A-Z, a-z, 0-9, +, /
  • Converts by repeatedly dividing by 64
The “All Representations” table appears after your first conversion, letting you instantly see and copy any base without switching modes.

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Error handling

The utility validates input and shows descriptive errors:
  • “Invalid Binary value. Base 2 (0-1)” for incorrect binary digits
  • “Invalid Hexadecimal value. Base 16 (0-9, A-F)” for invalid hex characters
  • “Please enter a value to convert” for empty input
  • Base64 encoder - For text encoding (different from numerical Base64)
  • Color converter - For converting color values between hex, RGB, and HSL

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