Introduction & Use Cases

Roman numerals (e.g., MMXXIV) are common on clocks, book chapters, and legal documents. Manual conversion is error-prone; with HeronTool's Roman Numeral (罗马数字) tool, you can convert instantly, supporting numbers from 1 to 3999.

Step 1: Arabic to Roman

  1. Visit HeronTool and locate the Roman Numeral (罗马数字) tool.
  2. Type a number like 1999 in the "Arabic number" input field, then click "Convert".
  3. The tool instantly outputs MCMXCIX and shows a copy button—click to copy the result.

Step 2: Roman to Arabic

  1. On the same tool page, switch to "Roman to Arabic" mode.
  2. Input e.g., MMXXIV and click "Convert".
  3. The result auto-displays as 2024, with validation notice (errors flagged if format is wrong).

Step 3: Batch Conversion & Validation

  • Supports multiple inputs separated by commas or newlines; outputs results line by line.
  • For invalid Roman numerals (e.g., "IIII"), the tool highlights the error and suggests the correct form (IV).

FAQ

Q: Does the tool support 0 or negative numbers?
A: No. Traditional Roman numerals have no zero or negatives; the tool restricts to 1-3999.

Q: How to quickly memorize common numbers?
A: Remember key symbols: I=1, V=5, X=10, L=50, C=100, D=500, M=1000.

Q: Can I export the conversion results?
A: Yes, the result area supports one-click copy, or you can manually save as a text file.