Roman Numerals Explained: Rules, Conversions, and History

Roman numerals have been used for over 2,000 years and remain present in modern life — from clock faces to movie credits, Super Bowl numbers to building cornerstones.

The 7 Roman numeral symbols

Symbol	Value
I	1
V	5
X	10
L	50
C	100
D	500
M	1,000

The rules

Additive rule: When a smaller value follows a larger one, add them.

• VI = 5 + 1 = 6
• LXIII = 50 + 10 + 1 + 1 + 1 = 63

Subtractive rule: When a smaller value precedes a larger one, subtract it.

• IV = 5 − 1 = 4
• IX = 10 − 1 = 9
• XL = 50 − 10 = 40
• XC = 100 − 10 = 90
• CD = 500 − 100 = 400
• CM = 1000 − 100 = 900

Repetition: A symbol can repeat up to 3 times (III = 3, XXX = 30). Never 4 times — use subtractive instead (IV not IIII).

How to convert a number to Roman numerals

Break the number into its place values and convert each:

Example: 2024

• 2000 = MM
• 0 (hundreds) = —
• 20 = XX
• 4 = IV
• 2024 = MMXXIV

Common years in Roman numerals

• 2024 = MMXXIV
• 2025 = MMXXV
• 2026 = MMXXVI
• 2000 = MM
• 1999 = MCMXCIX (the longest year under 2000)

Where you see Roman numerals today

• Clocks: Many clock faces use IIII instead of IV (tradition)
• Movies/TV: Copyright years in credits (© MMXXVI)
• Super Bowl: Super Bowl LIX = 59
• Monarchs: King Charles III, Pope Benedict XVI
• Tattoos: Birth years, anniversaries

Common mistakes

• Writing IIII instead of IV (only valid on clock faces)
• Writing VX instead of V (never subtract V, L, or D)
• Exceeding 3 repetitions (XXXX is wrong, use XL)

Convert any number or date with our Roman Numeral Converter — instant results with breakdown shown.