General
Roman Numeral Converter
Convert numbers to Roman numerals and back. Convert dates and years. Reference table always visible for quick lookup.
Enter a value and click Calculate
Quick Reference
I
1
V
5
X
10
L
50
C
100
D
500
M
1000
How is this calculated?
Number → Roman: greedily subtract largest symbols first
M=1000, CM=900, D=500, CD=400, C=100, XC=90...
Roman → Number: scan left to right
if current < next: subtract current, else add currentFAQ
Frequently asked questions about Roman numerals
How do Roman numerals work?
Roman numerals use seven symbols: I=1, V=5, X=10, L=50, C=100, D=500, M=1000. When a smaller numeral precedes a larger one, it is subtracted (IV=4). Otherwise, they are added (VI=6).
What is the largest number in Roman numerals?
Standard Roman numerals go up to 3999 (MMMCMXCIX). Beyond that, vinculum notation (overline) multiplies by 1000. Our converter supports 1–3,999,999 with overline notation.
How do I convert a year to Roman numerals?
Break the year into thousands, hundreds, tens, and ones. For example, 2024 = MM (2000) + XX (20) + IV (4) = MMXXIV.
What are the subtractive rules?
Only I, X, and C can be subtracted. I before V or X (4, 9). X before L or C (40, 90). C before D or M (400, 900). You cannot subtract more than one numeral at a time.
Can I convert dates to Roman numerals?
Yes! Use the Date tab to convert any date (day/month/year) to Roman numerals. Common for wedding dates, tattoos, and monuments.
Is this Roman numeral converter free?
Yes, completely free with no sign-up required. All conversions run in your browser — your data stays on your device and is never sent to any server.