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Roman Numeral Converter

Convert integers (1–3999) to Roman numerals and Roman numerals back to integers instantly.

What is Roman Numeral Converter?

The Roman Numeral Converter translates between standard Arabic integers (1–3999) and classical Roman numeral notation. It supports full subtractive notation (IV, IX, XL, XC, CD, CM) and validates input in both directions.

How to use

  1. 1 Select the conversion direction: Integer to Roman or Roman to Integer.
  2. 2 Enter your value in the input field.
  3. 3 Click Convert to see the result.
  4. 4 Integer input must be between 1 and 3999.
  5. 5 Roman numeral input must use valid characters: I, V, X, L, C, D, M.

Formula

Standard values: I=1, V=5, X=10, L=50, C=100, D=500, M=1000. Subtractive pairs: IV=4, IX=9, XL=40, XC=90, CD=400, CM=900. For integer→Roman, repeatedly subtract the largest value that fits.

Example calculation

2024 → MMXXIV (2000 + 20 + 4). MCMXCIX → 1000 + 900 + 90 + 9 = 1999.

Frequently asked questions

Why is there no zero in Roman numerals?

Roman numerals were developed for counting and commerce, where zero was not needed. The concept of zero as a number was introduced later from Indian mathematics.

What is subtractive notation?

Instead of writing IIII for 4, Romans wrote IV (one before five). The smaller numeral before a larger one means subtract. Only I, X, and C can be used subtractively.

Why stop at 3999?

Standard Roman numeral notation only supports up to 3999 (MMMCMXCIX) without special overline notation for larger values.

Are lowercase Roman numerals valid?

Lowercase roman numerals (i, v, x...) appear in outlines and page numbering. This converter uses uppercase, which is the standard form.

What year is MMXXVI?

MMXXVI = 2000 + 20 + 6 = 2026.