Roman Numeral Converter

About Roman Numeral Converter

Roman numerals use letters (I=1, V=5, X=10, L=50, C=100, D=500, M=1000). Subtractive notation: IV=4, IX=9.

How to use this calculator

1. Enter an Arabic number if you want its Roman numeral, or enter a Roman numeral if you want its Arabic value.
2. Check that the Roman numeral uses valid letters and correct subtraction rules, such as IV for 4 and IX for 9.
3. Click convert to see the matching numeral system instantly.
4. Use the result to verify dates, chapter numbers, or classic numbering in documents.

The formula explained

The conversion matches each value to Roman symbols and combines them using addition or subtraction rules. For example, 2024 becomes MMXXIV because 2000 is MM, 20 is XX, and 4 is IV.

• x = the Arabic number being converted
• n = the Roman numeral value after conversion

Step by step method

1. Break the number into thousands, hundreds, tens, and ones.
2. Write the Roman symbol for each place value, using subtraction forms when needed.
3. Combine the symbols from left to right to form the Roman numeral.

Worked example

Problem. Convert 2024 to a Roman numeral.

1. 2000 is MM, 20 is XX, and 4 is IV.
2. Put the parts together: MM + XX + IV.
3. The Roman numeral is MMXXIV.

Tips and common mistakes

• Use subtraction only in standard pairs like IV, IX, XL, XC, CD, and CM.
• Do not repeat I, X, C, or M more than three times in a row in standard Roman numerals.

Frequently asked questions