Roman Numeral Converter
Convert between Roman numerals and decimal numbers.
Conversion Input
Enter a number between 1 and 3999
Conversion Result
Roman Numeral
MMXXIV
Decimal
2024
About This Calculator
The Roman Numeral Converter converts between Roman numerals and decimal (Arabic) numbers. Roman numerals use letters to represent numbers: I (1), V (5), X (10), L (50), C (100), D (500), and M (1000).
This converter supports numbers from 1 to 3999. Enter either a decimal number to convert to Roman numerals, or enter Roman numerals to convert to decimal. The calculator handles both conversion directions automatically.
Formula & Calculation Method
Roman Numeral System:
Roman Numeral Values:
I = 1 | V = 5 | X = 10 | L = 50
C = 100 | D = 500 | M = 1000
Subtraction Rule:
When a smaller numeral appears before a larger one, subtract it
Examples: IV = 4, IX = 9, XL = 40, XC = 90
Addition Rule:
When numerals are in descending order, add them
Examples: VI = 6, XII = 12, XX = 20, CC = 200
Roman numerals use additive and subtractive notation. When a smaller value precedes a larger value, subtract it (e.g., IV = 4). When values are in descending order, add them (e.g., VI = 6). The maximum value is 3999 (MMMCMXCIX).
How to Use This Calculator
- Select Conversion Mode: Choose "Decimal to Roman" or "Roman to Decimal".
- Enter Value: Input either a decimal number (1-3999) or Roman numerals.
- View Results: See the converted value automatically displayed.
- Use Results: Use the converted values for dates, chapters, or other Roman numeral applications.
Frequently Asked Questions
What are Roman numerals?
Roman numerals are a numeral system that originated in ancient Rome. They use letters to represent numbers: I (1), V (5), X (10), L (50), C (100), D (500), and M (1000). They are still used today for things like years, chapter numbers, and clock faces.
How do Roman numerals work?
Roman numerals use additive and subtractive notation. When a smaller value precedes a larger value, you subtract it (IV = 4, IX = 9). When values are in descending order, you add them (VI = 6, XII = 12).
What is the maximum Roman numeral?
The standard Roman numeral system supports numbers up to 3999 (MMMCMXCIX). Beyond that, additional notation is needed. This converter supports numbers from 1 to 3999.
Where are Roman numerals used today?
Roman numerals are still used for: years (e.g., MMXXIV for 2024), chapter numbers in books, movie release dates, clock faces, page numbers in prefaces, and numbering of monarchs or popes.
Calculator by
NumCalculators Editorial Team
Multi-disciplinary Expert Team