Roman Numeral Converter
Convert between Roman numerals and Arabic numbers instantly. Enter a number (1-3999) or a Roman numeral (I- MMMCMXCIX) and get the equivalent in both formats with a detailed breakdown. Perfect for students, historians, and anyone working with ancient numbering systems.
What Are Roman Numerals?
Roman numerals are a numeral system that originated in ancient Rome and were used throughout the Roman Empire. They use combinations of letters from the Latin alphabet to represent numbers. The system is based on seven symbols:
- I = 1
- V = 5
- X = 10
- L = 50
- C = 100
- D = 500
- M = 1000
Roman numerals are written from largest to smallest value, with subtractive notation used for certain combinations (e.g., IV = 4, IX = 9, XL = 40, XC = 90, CD = 400, CM = 900).
How the Roman Numeral Converter Works
The converter works in both directions:
Arabic â Roman:
The number is broken down into thousands, hundreds, tens, and ones, then each part is converted using the Roman numeral mapping. The results are combined in order.
Roman â Arabic:
Each Roman numeral character is converted to its numeric value. If a smaller value appears before a larger value, it is subtracted; otherwise, it is added.
For example: 2024 = 2000 (MM) + 20 (XX) + 4 (IV) = MMXXIV.
Common Roman Numerals
- I = 1, II = 2, III = 3, IV = 4, V = 5
- VI = 6, VII = 7, VIII = 8, IX = 9, X = 10
- XX = 20, XXX = 30, XL = 40, L = 50
- LX = 60, LXX = 70, LXXX = 80, XC = 90
- C = 100, CC = 200, CCC = 300, CD = 400
- D = 500, DC = 600, DCC = 700, DCCC = 800
- CM = 900, M = 1000
â Roman Numeral Converter FAQ
What is a Roman numeral?
A Roman numeral is a number represented by letters from the Latin alphabet. The system uses seven symbols: I (1), V (5), X (10), L (50), C (100), D (500), and M (1000).
How do I convert Arabic numbers to Roman numerals?
Break the number into thousands, hundreds, tens, and ones. Convert each part using the Roman numeral mapping (e.g., 4 = IV, 9 = IX, 40 = XL, 90 = XC, 400 = CD, 900 = CM). This converter does this automatically for you.
How do I convert Roman numerals to Arabic numbers?
Read the Roman numeral from left to right. If a smaller value precedes a larger value, subtract it; otherwise, add it. For example, MCMXCIV = 1000 + (1000-100) + (100-10) + (5-1) = 1994.
What is the largest number that can be represented in Roman numerals?
Using the standard symbols (I, V, X, L, C, D, M), the largest number is 3999 (MMMCMXCIX). This converter supports numbers from 1 to 3999.
What is the smallest number in Roman numerals?
The smallest number is 1, represented by the symbol I. This converter supports numbers from 1 to 3999.
What is the subtractive principle in Roman numerals?
The subtractive principle means that when a smaller numeral appears before a larger one, it is subtracted. For example, IV = 4 (5-1), IX = 9 (10-1), XL = 40 (50-10), XC = 90 (100-10), CD = 400 (500-100), CM = 900 (1000-100).
Why is 4 written as IV and not IIII?
In modern Roman numeral usage, IV (5-1) is the standard representation for 4. The additive form IIII was used in ancient Rome but is rarely seen today except on some clocks and watches.
Why is 9 written as IX and not VIIII?
IX (10-1) is the standard representation for 9 using the subtractive principle. The additive form VIIII is outdated and not used in modern Roman numeral notation.
What is the Roman numeral for 1000?
The Roman numeral for 1000 is M.
What is the Roman numeral for 2024?
2024 in Roman numerals is MMXXIV (2000 + 20 + 4 = MMXXIV).
What is the Roman numeral for 1999?
1999 in Roman numerals is MCMXCIX (1000 + 900 + 90 + 9 = MCMXCIX).
What are the rules for writing Roman numerals?
The main rules are: numerals are written from largest to smallest; only one smaller numeral can precede a larger one for subtraction (e.g., IV, IX, XL, XC, CD, CM); I, X, C, and M can be repeated up to three times; V, L, and D cannot be repeated.
What is the Roman numeral for 0?
There is no Roman numeral for zero. The concept of zero was not part of the Roman numeral system. This converter supports numbers starting from 1.
How do you write large numbers in Roman numerals?
For numbers larger than 3999, a bar (vinculum) placed over a numeral multiplies its value by 1000. For example, VĖ = 5000. This converter focuses on numbers 1-3999 using standard notation.
What is the difference between Roman numerals and Arabic numerals?
Roman numerals use letters (I, V, X, L, C, D, M) to represent numbers. Arabic numerals use the digits 0-9 in a positional system (e.g., 1, 2, 3). Arabic numerals are the standard system used worldwide today.
Where are Roman numerals still used today?
Roman numerals are still used in many contexts: on clock faces, in book chapters and volume numbers, for movie sequels (e.g., Rocky IV), for monarchs (e.g., King Henry VIII), and in the Super Bowl numbering (e.g., Super Bowl LVIII).
What is the Roman numeral for 50?
The Roman numeral for 50 is L.
What is the Roman numeral for 100?
The Roman numeral for 100 is C.
What is the Roman numeral for 500?
The Roman numeral for 500 is D.
Is this Roman numeral converter accurate?
Yes. This converter follows the standard rules of Roman numeral notation and supports numbers from 1 to 3999. It correctly handles subtractive notation (IV, IX, XL, XC, CD, CM) and provides a detailed breakdown of the conversion.