Roman Numeral Converter
Convert between Roman and Arabic numerals
Roman Numeral Converter
Convert between Roman numerals and Arabic numbers (1-3999)
Enter a number between 1 and 3999
OR
Use symbols: I, V, X, L, C, D, M
Conversion Result
Arabic Number
42
Roman Numeral
XLII
Roman Numeral Breakdown
XL (40 each)1 × 40 = 40
I (1 each)2 × 1 = 2
Why limit to 3999?
Standard Roman numerals don't have symbols for 5000 or higher. The highest is M (1000), and traditionally, symbols aren't repeated more than 3 times. So 3999 (MMMCMXCIX) is the highest number possible with basic Roman numeral rules.
Basic Symbols:
I = 1
V = 5
X = 10
L = 50
C = 100
D = 500
M = 1000
Subtraction Rules: Only I, X, and C can be subtracted from larger numerals (e.g., IV = 4, IX = 9, CD = 400).
Roman Numeral Reference
Common Conversions
Essential Roman numeral patterns and examples
| Arabic | Roman | Note |
|---|---|---|
| 1 | I | Basic unit |
| 4 | IV | Subtractive notation |
| 5 | V | Basic symbol |
| 9 | IX | Subtractive notation |
| 10 | X | Basic symbol |
| 40 | XL | XL = 50 - 10 |
| 50 | L | Basic symbol |
| 90 | XC | XC = 100 - 10 |
| 100 | C | Basic symbol |
| 400 | CD | CD = 500 - 100 |
| 500 | D | Basic symbol |
| 900 | CM | CM = 1000 - 100 |
| 1000 | M | Basic symbol |
| 1994 | MCMXCIV | Complex example |
| 2024 | MMXXIV | Current year |
| 3999 | MMMCMXCIX | Maximum value |
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Frequently Asked Questions
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