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Base Convert is a free, open-source tool for converting numbers between binary, hexadecimal, Roman numerals, balanced ternary, and dozens of other numeral systems. All calculations happen instantly in your browser.
Features
- Arbitrary precision - up to 1000 decimal places via high-precision mode
- IEEE 754 analysis - inspect floating-point bit patterns with the IEEE 754 converter
- URL sharing - state is persisted in the URL for easy sharing
- PWA installable - add to home screen for offline access
- Open source - view source on Codeberg
Supported Systems
- Standard positional bases (2-10000) - binary, octal, hexadecimal, and any radix
- Balanced bases - symmetric digits around zero (balanced ternary)
- Bijective bases - no zero digit, like Excel columns
- Negative bases - represent negative numbers without a sign (negabinary, negadecimal)
- Non-integer bases - phinary, base e, base pi
- Complex bases - quater-imaginary, twindragon
- Mixed-radix - factorial, primorial
- Binary encodings - Gray code, two's complement
- Historical & simple - Roman numerals, unary
Number Formats
| Feature | Syntax | Example |
|---|---|---|
| Colon notation | digit:digit.digit | 1:30.15 (base 60) |
| Colon notation is accepted as input for all numeric bases. It is used for output in bases 37+, balanced bases, and mixed-radix systems. | ||
| Complex numbers | a+bi or a-bi | 3+4i |
Enter complex numbers in numeric bases. Both i and j are accepted. | ||
| Balanced ternary | T, 0, 1 | 1T0 (T = -1) |
| T represents −1. Other balanced bases use colon notation with negative digits. | ||
| Negative digits | -digit in colon notation | -2:1 or 2̄1 |
| Used in balanced bases where digits can be negative. The overline character (2̄) also works. | ||
| Roman numerals | parentheses = ×1000 | (X)(V) = 15000 |
| Parentheses multiply by 1000, enabling numbers into the millions. | ||
Input Normalization
- Thousand separators ignored - spaces, underscores, and apostrophes (
1 000,1_000,1'000) - European decimal comma - converted to period when unambiguous (
3,14→3.14) - Typographic dashes - en-dash, em-dash, and minus sign all treated as minus
- Base prefixes -
0xFFin a hex field is read asFF
Keyboard Shortcuts
| ? | Show keyboard shortcuts |
| / or Ctrl+K | Search systems |
| Ctrl+Shift+C | Copy all conversions |
| ↑ / ↓ | Navigate cards |
| Escape | Close dialog / blur input |