Roman Numeral Converter

Convert between Arabic numbers and Roman numerals (I, V, X, L, C, D, M).

Category: Converters

When to use?

Use it to read Roman numerals on clock faces, movie production years, or chapter numbers as Arabic numbers, or to write a number as a Roman numeral.

How to use

  • Enter an Arabic number to convert to a Roman numeral.
  • Or enter a Roman numeral to convert to an Arabic number.

Input Explanation

Enter a positive integer (1–3999) to convert to Roman, or a Roman numeral (e.g. XIV) to read as an Arabic number.

Calculation Basis

For Arabic input, it iterates per-digit mapped Roman arrays (M, CM, D, C, etc.) and sums; for Roman input, it subtracts when a later symbol is larger (e.g. IV).

Usage Examples

  • Read Roman numerals - Convert Roman numerals on clocks or movie years to Arabic numbers.
  • Write Roman numerals - Convert a number when you need Roman numeral notation.
  • Number chapters - Convert when numbering book or document chapters in Roman numerals.

Examples

  • 2024 → MMXXIV
  • XIV → 14

Cautions

  • Malformed input can cause parsing errors or broken output.
  • Standard Roman numerals are limited, so values are typically expressed only up to 3999.

Guides

Roman numeral rules

I=1, V=5, X=10, L=50, C=100, D=500, M=1000. A smaller value before a larger one means subtraction (IV=4, IX=9).

Where they appear

You see Roman numerals in movie titles, royal sequences, clock faces, and book chapter numbers. Values above 4000 are hard to express in standard Roman numerals.

FAQ

What number range is supported?

It converts 1 to 3999.

Are lowercase Roman numerals recognized?

Yes, lowercase like i, v, x are recognized.

Why not above 4000?

Standard Roman notation has M (1000) as the largest symbol, so it typically goes up to 3999.

What are the Roman numeral rules?

List I, V, X, L, C, D, M from largest; a smaller symbol before a larger one (IV, IX) means subtraction.

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