Math
Roman Numeral Converter
Numbers to Roman numerals and back, symbol by symbol
Type a number (for example, 2026) or a Roman numeral (for example, MMXXVI): this roman numeral converter detects which way to convert on its own.
The key idea
MIM is not 1999: Roman numerals only subtract in six ways
In standard modern notation, a letter is never repeated more than three times in a row, so 4 is IV and 9 is IX. There are only six valid subtractions: IV, IX, XL, XC, CD and CM. That is why 1999 is written MCMXCIX, not MIM, and the converter warns you if you write it wrong.
How it is calculated
Roman numerals use seven letters: I (1), V (5), X (10), L (50), C (100), D (500) and M (1,000).
You add them from left to right, except when a smaller letter comes before a larger one: then you subtract it (IV = 4, IX = 9, XL = 40, XC = 90, CD = 400, CM = 900).
The same letter is never repeated more than three times in a row, and V, L and D are never repeated. That is why the largest standard numeral is MMMCMXCIX (3,999).
Worked example
2026 = MM (2,000) + XX (20) + VI (6) = MMXXVI. And MCMXCIX = 1,000 + 900 + 90 + 9 = 1999.
Typical cases
Roman numerals 1 to 100
The numbers 1 to 20 and the tens up to 100. Any other number is built from these: 47 is XL plus VII, XLVII.
| 1 to 10 | 11 to 20 | Tens to 100 |
|---|---|---|
| 1 = I | 11 = XI | 10 = X |
| 2 = II | 12 = XII | 20 = XX |
| 3 = III | 13 = XIII | 30 = XXX |
| 4 = IV | 14 = XIV | 40 = XL |
| 5 = V | 15 = XV | 50 = L |
| 6 = VI | 16 = XVI | 60 = LX |
| 7 = VII | 17 = XVII | 70 = LXX |
| 8 = VIII | 18 = XVIII | 80 = LXXX |
| 9 = IX | 19 = XIX | 90 = XC |
| 10 = X | 20 = XX | 100 = C |
Save or share this table as an image Typical cases
Years in Roman numerals
Common years written in Roman numerals, for tattoos, cornerstones and movie credits.
| Year | Roman numeral |
|---|---|
| 1776 | MDCCLXXVI |
| 1900 | MCM |
| 1950 | MCML |
| 1980 | MCMLXXX |
| 1990 | MCMXC |
| 1999 | MCMXCIX |
| 2000 | MM |
| 2010 | MMX |
| 2020 | MMXX |
| 2024 | MMXXIV |
| 2025 | MMXXV |
| 2026 | MMXXVI |
| 2027 | MMXXVII |
| 2028 | MMXXVIII |
Save or share this table as an image Common questions
Frequently asked questions
How do you write zero in Roman numerals?
You do not: the Romans had no symbol for zero. That is why the converter starts at 1.
What about numbers above 3,999?
They were written with a bar over the letter, which multiplies its value by 1,000: V with a bar is 5,000. It is rarely used today, and the converter goes up to 3,999 (MMMCMXCIX).
How do you write 2026 in Roman numerals?
MMXXVI: MM (2,000) + XX (20) + VI (6).
How do you read XLIX?
It is 49: XL (40) + IX (9). A common mistake is writing IL, which is not valid because I only subtracts before V and X.
Why do some clocks show IIII instead of IV?
It is a clockmaking tradition, not the standard form under today's rules. In text, an outline or a date, write IV.
Where are Roman numerals used today?
In Super Bowl numbers (Super Bowl LX), names of monarchs and popes (Elizabeth II), movie sequels, book chapters and volumes, outlines and copyright years in film credits. Clock faces and building cornerstones use them too.
Geometry and conversions
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