Roman Numeral Converter

Convert any number from 1 to 3999 to Roman numerals, or decode any Roman numeral back to a decimal number. Validates input and shows a reference table of standard symbols.

Roman Numeral Reference

I

1

V

5

X

10

L

50

C

100

D

500

M

1000

IV

= 4

IX

= 9

XL

= 40

XC

= 90

CD

= 400

CM

= 900

Roman Numeral Rules

Roman numerals use seven symbols combined according to addition and subtraction rules:

  • Repetition adds: III = 3, XXX = 30, MMM = 3000.
  • A symbol before a larger one subtracts: IV = 4, IX = 9, XL = 40, XC = 90, CD = 400, CM = 900.
  • Maximum repetition: A symbol can repeat at most 3 times consecutively (III but not IIII; XXX but not XXXX).
  • Subtractive pairs: Only I, X, C can be used subtractively — and only before the next two higher values.

Year Conversion Table

YearRoman Numeral
2025MMXXV
2024MMXXIV
2023MMXXIII
2000MM
1999MCMXCIX
1900MCM
1776MDCCLXXVI
1000M

Frequently Asked Questions

What is 2025 in Roman numerals?

2025 in Roman numerals is MMXXV. MM = 2000, XX = 20, V = 5.

What is MMXXIV in numbers?

MMXXIV in decimal is 2024. MM = 2000, XX = 20, IV = 4.

What is the largest number in Roman numerals?

The traditional Roman numeral system goes up to 3999 (MMMCMXCIX). Numbers above 3999 required special notation (vinculum/overline) which is not standard in everyday use.

What are the basic Roman numeral symbols?

The seven basic symbols are: I=1, V=5, X=10, L=50, C=100, D=500, M=1000. All other numbers are formed by combining these using addition and subtraction rules.

What is the subtraction rule in Roman numerals?

When a smaller numeral appears before a larger one, it is subtracted. IV=4 (5-1), IX=9 (10-1), XL=40, XC=90, CD=400, CM=900. Only I, X, and C can be used as subtractive numerals.

What is 1000 in Roman numerals?

1000 in Roman numerals is M.

Are Roman numerals still used today?

Yes. Roman numerals are used for clock faces, chapter numbers in books, movie sequels (Rocky IV, Fast X), year of production on films/TV, Super Bowl numbering, and monarchs' regnal numbers (King Charles III).

How do I write 4 in Roman numerals?

4 in Roman numerals is IV. This uses the subtractive notation: I (1) placed before V (5) means 5 − 1 = 4. The older additive form IIII is still seen on some clock faces but IV is standard.

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