General
Roman Numeral Converter
Convert numbers between Roman numerals and decimal numbers instantly.
Enter a value to see the conversion result
Related to Roman Numeral Converter
The Roman Numeral Converter is a tool that converts numbers between decimal (standard numbers) and Roman numerals. It supports both conversion directions and follows the standard rules of Roman numeral notation, handling numbers from 1 to 3999.
Roman Numeral System
Roman numerals use seven basic symbols: I (1), V (5), X (10), L (50), C (100), D (500), and M (1000). Numbers are written by combining these symbols, generally from left to right in descending order. When a smaller value appears before a larger value, it indicates subtraction.
Conversion Rules
• Numbers are written from left to right, largest to smallest
• A smaller numeral before a larger one means subtraction (e.g., IV = 4)
• The same symbol cannot be repeated more than three times in succession
• Only I, X, C, and M can be repeated
• Only I, X, and C can be used as subtractive numerals
The converter provides instant results in both directions, with clear explanations of the conversion process. Understanding the output depends on your conversion direction.
Number to Roman
When converting from a decimal number to Roman numerals, the result shows how the number is represented using Roman numeral symbols. For example, 1994 becomes MCMXCIV, using the subtractive notation where needed.
Roman to Number
When converting from Roman numerals to decimal numbers, the result shows the equivalent decimal value. The converter validates the Roman numeral input to ensure it follows proper formation rules before performing the conversion.
1. What is the largest number I can convert?
The calculator can convert numbers from 1 to 3999. This limit exists because traditional Roman numerals don't have a symbol for 5000 or larger numbers, and 4000 would require a notation system that isn't universally accepted.
2. Why can't I use certain combinations of Roman numerals?
Roman numerals follow strict rules about which combinations are valid. For example, you can't repeat the same symbol more than three times in succession (except for M), and only certain symbols (I, X, C) can be used in subtractive combinations.
3. How do I know if my Roman numeral is correct?
A valid Roman numeral follows these rules: symbols are arranged from largest to smallest (except for subtractive combinations), no more than three identical symbols in a row, and only I, X, and C can appear before larger values to indicate subtraction.
4. Can Roman numerals represent decimal numbers or zero?
Traditional Roman numerals cannot represent zero or decimal numbers. The system was developed for counting whole numbers only. The concept of zero was not part of the Roman number system, and fractions were handled differently in Roman mathematics.
5. What is the scientific source for this calculator?
This calculator implements the standard Roman numeral system as documented in mathematical and historical sources. The conversion rules follow the conventions established in classical Latin texts and standardized by mathematical historians. The implementation adheres to the guidelines presented in "Numbers Through the Ages" by Georges Ifrah and "The Development of Mathematics" by E.T. Bell, which detail the historical development and standardization of Roman numerals.