Number Base Converter
Convert between binary, octal, decimal, and hexadecimal.
BinaryOctalDecimalHex
| Binary | 11111111 |
| Octal | 377 |
| Decimal | 255 |
| Hex | FF |
Click any row to copy that single result.
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About Number Bases
A number base (or radix) is how many distinct digits a system uses. Choose the base of your input value and the converter shows the binary, octal, decimal, and hexadecimal equivalents at once — click any row to copy a single result.
Common Bases
| Base | Name | Digits | Example (decimal 255) |
|---|---|---|---|
| 2 | Binary | 0–1 | 11111111 |
| 8 | Octal | 0–7 | 377 |
| 10 | Decimal | 0–9 | 255 |
| 16 | Hexadecimal | 0–9, A–F | FF |
Conversion is limited to whole numbers within JavaScript’s safe integer range (about 9 × 10¹⁵).
Frequently Asked Questions
- How do I convert decimal to binary?
- Set the input base to Decimal and type your number — the binary, octal, and hexadecimal results appear instantly below.
- What is hexadecimal?
- Hexadecimal (base 16) counts using the digits 0–9 and the letters A–F, where A=10 through F=15. It is widely used in programming, colour codes and memory addresses.
- How big a number can I convert?
- Conversion works on whole numbers up to JavaScript’s safe integer limit (about 9 × 10¹⁵, or 2⁵³ − 1). Larger values may lose precision.
- Does it handle negative numbers or fractions?
- This tool converts non-negative whole numbers only. Decimal fractions and negative signs are not supported.
📅 Last updated: June 2026 · Formulas follow standard banking / tax conventions · Results are for reference only.