Roman numerals are a number system originating in ancient Rome, still used today for clock faces, book chapters, movie sequel numbers, Super Bowl names, and year numbers in formal contexts. The system uses seven symbols to represent values.
The seven symbols
| Symbol | Value |
|---|---|
| I | 1 |
| V | 5 |
| X | 10 |
| L | 50 |
| C | 100 |
| D | 500 |
| M | 1,000 |
The additive rule
When a smaller or equal value follows a larger value, you add them:
- VI = 5 + 1 = 6
- VIII = 5 + 1 + 1 + 1 = 8
- XII = 10 + 1 + 1 = 12
- LX = 50 + 10 = 60
The subtractive rule
When a smaller value appears before a larger value, subtract it. Only six combinations are valid:
| Notation | Value | Meaning |
|---|---|---|
| IV | 4 | 5 − 1 |
| IX | 9 | 10 − 1 |
| XL | 40 | 50 − 10 |
| XC | 90 | 100 − 10 |
| CD | 400 | 500 − 100 |
| CM | 900 | 1,000 − 100 |
No other subtractive combinations are valid. "IC" for 99 is incorrect — the correct form is XCIX.
Common numbers in Roman numerals
| Number | Roman | Number | Roman |
|---|---|---|---|
| 1 | I | 20 | XX |
| 2 | II | 30 | XXX |
| 3 | III | 40 | XL |
| 4 | IV | 50 | L |
| 5 | V | 90 | XC |
| 6 | VI | 100 | C |
| 7 | VII | 400 | CD |
| 8 | VIII | 500 | D |
| 9 | IX | 900 | CM |
| 10 | X | 1,000 | M |
Year numbers in Roman numerals
| Year | Roman numerals |
|---|---|
| 2020 | MMXX |
| 2021 | MMXXI |
| 2022 | MMXXII |
| 2023 | MMXXIII |
| 2024 | MMXXIV |
| 2025 | MMXXV |
| 2026 | MMXXVI |
Numbers above 3,999: vinculum notation
Standard Roman numerals only go to 3,999 (MMMCMXCIX). For larger numbers, a bar (vinculum) is placed over a symbol to multiply it by 1,000:
- V̄ = 5,000
- X̄ = 10,000
- L̄ = 50,000
- C̄ = 100,000
- D̄ = 500,000
- M̄ = 1,000,000
So 1,000,000 is M̄ and 3,999,999 is M̄M̄M̄C̄M̄X̄C̄M̄X̄M̄V̄CMXCIX.
Where Roman numerals are used today
- Clock faces: Most analog clocks use IIII instead of IV (a historical exception for visual balance)
- Movie sequels: Rocky II, Star Wars Episode IV, The Godfather Part II
- Super Bowl: Super Bowl LVIII (58), Super Bowl LIX (59)
- Monarchs and popes: King Charles III, Pope John Paul II
- Book front matter: Preface and contents page numbers
- Copyright years: © MMXXV in movie credits
- Outlines: I. Introduction, II. Background, III. Analysis
How to convert Roman numerals free
- Go to Roman Numeral Converter
- Toggle between Number → Roman or Roman → Number mode
- Enter your value — conversion is instant
- Use batch mode to convert up to 100 numbers at once and download as a .txt file
- Click quick examples to populate common values instantly