Roman Numerals Converter
Convert between Roman numerals and Arabic numbers (1 to 3999). Auto-detects direction, validates strict subtractive notation, and shows a reference table.
Roman numerals converter
Direction is detected automatically. Roman numerals must be uppercase and within 1 to 3999.
Arabic
2,026
Roman
MMXXVI
Reference table
I
1
V
5
X
10
L
50
C
100
D
500
M
1,000
Subtractive pairs: IV (4), IX (9), XL (40), XC (90), CD (400), CM (900).
Frequently Asked Questions about the Roman Numerals Converter
What is subtractive notation in Roman numerals?
Subtractive notation writes a smaller symbol before a larger one to mean subtraction. Only six pairs are valid: IV (4), IX (9), XL (40), XC (90), CD (400), and CM (900). So 4 is IV, not IIII, and 1994 is MCMXCIV.
Why is MMMM not a valid Roman numeral?
Standard Roman numerals only allow up to three of the same symbol in a row, which caps M at MMM (3000). The highest representable value is MMMCMXCIX (3999). Anything from 4000 upward needs non-standard overlines or other extensions, so this converter rejects it.
How do you write zero in Roman numerals?
You don't. The Roman system has no symbol for zero because it grew out of counting tally marks, where nothing simply was not recorded. The medieval scholar Bede later used the word nulla as a placeholder, but no numeral exists, which is why this tool only accepts 1 to 3999.
Where are Roman numerals still used today?
They appear in Super Bowl numbering (Super Bowl LIX is 59), on clock faces, in book chapters and movie sequels (Rocky IV), in royal and papal names (Elizabeth II, Pope John XXIII), and in copyright dates at the end of films and broadcasts.
How do I read Roman numeral dates on old buildings?
Read from left to right, adding values, except when a smaller symbol comes before a larger one (then subtract). For example, MDCCLXXVI breaks down as M (1000) + D (500) + CC (200) + L (50) + XX (20) + V (5) + I (1) = 1776.