Roman Numeral Converter
Convert between numbers and Roman numerals instantly.
Batch Results
| Number | Roman Numeral |
|---|
Roman Numeral Reference
| Roman | Value |
|---|---|
| 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 | 1,000 |
This tool is for informational and educational purposes only. It is not a substitute for professional financial, medical, legal, or engineering advice. See Terms of Service.
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Request a ToolHow to Use the Roman Numeral Converter
This tool converts numbers to Roman numerals and Roman numerals back to numbers. It supports four modes so you can work with single values, lists, or years.
- Choose a mode. Use the dropdown at the top to select Decimal to Roman, Roman to Decimal, Batch Convert, or Year Converter. The input field changes to match your selection.
- Enter your value. Type a number between 1 and 3,999 for decimal mode, a valid Roman numeral like XIV or MMXXVI for Roman mode, multiple numbers on separate lines for batch mode, or a year for year mode.
- Read the result. The conversion appears instantly as you type. For batch mode, results display in a table below the input.
- Copy or share. Use the Copy button to grab the result to your clipboard, or the Share button to generate a link with your inputs pre-filled so others can see the same conversion.
The quick-reference table at the bottom lists every Roman numeral symbol and its value, including the six subtractive combinations (IV, IX, XL, XC, CD, CM).
About Roman Numerals
Roman numerals originated in ancient Rome and use combinations of seven letters to represent values: I (1), V (5), X (10), L (50), C (100), D (500), and M (1,000). Numbers are formed by adding symbol values together from left to right. For example, VIII equals 5 + 1 + 1 + 1 = 8.
The system also uses subtractive notation, where a smaller value placed before a larger one means subtraction. IV equals 4 (5 minus 1), IX equals 9, XL equals 40, XC equals 90, CD equals 400, and CM equals 900. Standard Roman numerals can represent values from 1 to 3,999. The number 4,000 and above would require extended notation with overlines, which is rarely used in practice.
Today, Roman numerals appear on clock faces, in film and television credits (copyright years), on building cornerstones, in book chapter numbering, for Super Bowl editions, and in formal outlines. They remain a common way to add a classical or formal look to dates and numbering.
Frequently Asked Questions
What are the basic Roman numerals?
The seven basic Roman numeral symbols are I (1), V (5), X (10), L (50), C (100), D (500), and M (1,000). All Roman numerals are built from combinations of these seven symbols using additive and subtractive rules.
What is the largest number in Roman numerals?
Using standard notation, the largest Roman numeral is MMMCMXCIX, which equals 3,999. To represent 4,000 and above, an extended system uses a bar (vinculum) over a numeral to multiply its value by 1,000. However, this extended notation is rarely used today.
How do you write years in Roman numerals?
Convert each part of the year using standard Roman numeral rules. For example, 2026 breaks down as MM (2000) + XX (20) + VI (6) = MMXXVI. The year 1999 is MCMXCIX: M (1000) + CM (900) + XC (90) + IX (9). You will often see Roman numeral years in film credits and on building cornerstones.
Why are Roman numerals still used today?
Roman numerals are used for their formal and traditional appearance. Common uses include clock and watch faces, copyright dates in film and TV credits, chapter and volume numbering in books, Super Bowl numbering, building dedication dates, and formal outlines. They add a sense of permanence and classical style that Arabic numerals do not convey.