Roman Numeral Converter
How to Use
Select the conversion direction and enter a value. For Number → Roman, enter an integer from 1 to 3999. For Roman → Number, enter a Roman numeral (e.g., XIV). The result updates instantly.
What are Roman Numerals?
Roman numerals are a numeral system originating in ancient Rome, used throughout the Roman Empire and across Europe for centuries. Unlike the modern decimal system with place values, Roman numerals use combinations of letters to represent values. The system was the dominant form of numerical notation in Europe until the late Middle Ages, when Hindu-Arabic numerals gradually replaced it. Today, Roman numerals remain in common use for clock faces, book chapters, movie sequel numbering, Super Bowl editions, and formal documents such as outlines and legal texts.
Roman Numeral System
Roman numerals use seven symbols: I (1), V (5), X (10), L (50), C (100), D (500), M (1000). Subtractive notation is used for 4, 9, 40, 90, 400, and 900 (e.g., IV = 4, XC = 90). The standard system covers values from 1 to 3999.
Common Use Cases
- Education — learn and practice converting between Roman and Arabic numeral systems
- Clock faces — read and interpret traditional clock displays that use Roman numerals
- Movie and event dates — decode copyright years (MMXXVI = 2026) or sequel numbers in film and media
- Chapter and outline numbering — convert numbers for use in book chapters, legal documents, and formal outlines
- Historical dates — read dates inscribed on buildings, monuments, and historical documents
Reference Table
I = 1, IV = 4, V = 5, IX = 9, X = 10, XL = 40, L = 50, XC = 90, C = 100, CD = 400, D = 500, CM = 900, M = 1000. To form a number, combine symbols from largest to smallest. For example: 2024 = MMXXIV (1000 + 1000 + 10 + 10 + 4). When a smaller value appears before a larger one, it is subtracted (IV = 5 - 1 = 4).
Privacy
All processing happens in your browser. No data is sent to any server.
FAQ
What is the difference between Roman and Arabic numerals?
Arabic numerals (0-9) use place value, where a digit's position determines its weight. Roman numerals instead combine seven symbols — I, V, X, L, C, D, M — using addition and subtraction. Roman numerals also have no way to express zero, negatives, or decimals.
Is the value I enter sent to a server?
No. All conversion runs in your browser with JavaScript, and the numbers or Roman numerals you type are never sent to or stored on any server.
Why can it only convert numbers from 1 to 3999?
3999 (MMMCMXCIX) is the largest value standard Roman numerals can represent. Values of 4000 and above require the vinculum (an overline meaning ×1000), which is non-standard, so this tool does not support it.
Can I convert lowercase Roman numerals like xiv?
Roman numerals are conventionally written in uppercase. Lowercase input may be treated as an invalid Roman numeral, so we recommend entering them in uppercase, such as XIV.
What is subtractive notation?
It places a smaller symbol before a larger one to express the difference. For example, IV means 5 − 1 = 4 and XC means 100 − 10 = 90, letting you write IV instead of the longer IIII.