Ⅻ Math & Number Tools

Roman Numeral Converter

Convert decimal numbers to Roman numerals and Roman numerals back to decimal. Supports 1 to 3,999 with step-by-step breakdown.

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Roman Numeral Reference
The 13 core symbols and their values
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

Frequently Asked Questions

How do Roman numerals work?
Roman numerals use letters to represent values: I=1, V=5, X=10, L=50, C=100, D=500, M=1000. When a smaller value precedes a larger one (like IV), it is subtracted. When it follows (like VI), it is added. This subtractive notation allows compact representation.
What is the largest Roman numeral?
Using standard notation, the largest Roman numeral is MMMCMXCIX = 3,999. The symbol M can repeat up to 3 times. Numbers beyond 3,999 require special extensions like a vinculum (bar over a numeral, multiplying it by 1,000).
Why is 4 written as IV and not IIII?
The subtractive notation (IV for 4, IX for 9, etc.) became the standard form to avoid repetitive sequences and keep numerals compact. However, IIII was historically used — you may still see it on clock faces.
Where are Roman numerals used today?
Roman numerals are still used for clock faces, book chapters and volume numbers, movie sequels (Rocky IV), year dates on buildings and films, Super Bowl numbering, and formal outlines and lists.
How do you write the year 2024 in Roman numerals?
2024 = MMXXIV. Breaking it down: MM=2000, XX=20, IV=4. So 2000 + 20 + 4 = 2024.