Roman Numeral Converter Guide: Rules, Charts & Examples
Quick Answer
- *Roman numerals use 7 symbols: I (1), V (5), X (10), L (50), C (100), D (500), M (1000).
- *Subtractive rule: a smaller numeral before a larger one means subtract (IV = 4, IX = 9, XL = 40).
- *The largest standard Roman numeral is MMMCMXCIX (3,999).
- *To convert, break the number into place values and convert each part separately.
The 7 Roman Numeral Symbols
The entire Roman numeral system is built from just seven letters. Every number from 1 to 3,999 is a combination of these symbols.
| Symbol | Value | Origin |
|---|---|---|
| I | 1 | Single tally mark |
| V | 5 | Hand with five fingers (V shape) |
| X | 10 | Two V shapes, one inverted |
| L | 50 | Originally a superimposed V and I |
| C | 100 | From Latin “centum” (hundred) |
| D | 500 | Half of the symbol for 1,000 |
| M | 1,000 | From Latin “mille” (thousand) |
Roman numerals originated around 900–800 BC and were the dominant number system in Europe for over 1,500 years until Hindu-Arabic numerals (1, 2, 3...) gradually replaced them starting in the 13th century. According to the Encyclopaedia Britannica, the earliest known use of subtractive notation appears in inscriptions from the 1st century BC.
Three Rules for Reading Roman Numerals
Rule 1: Addition
When a symbol of equal or lesser value appears after a larger symbol, add the values together. VII = 5 + 1 + 1 = 7. CLXVI = 100 + 50 + 10 + 5 + 1 = 166.
Rule 2: Subtraction
When a smaller symbol appears before a larger one, subtract the smaller from the larger. IV = 5 – 1 = 4. XC= 100 – 10 = 90. Only I, X, and C can be used as subtractive prefixes, and each can only precede the two symbols immediately larger than it.
| Subtractive Pair | Value | Used For |
|---|---|---|
| IV | 4 | Ones place |
| IX | 9 | Ones place |
| XL | 40 | Tens place |
| XC | 90 | Tens place |
| CD | 400 | Hundreds place |
| CM | 900 | Hundreds place |
Rule 3: Repetition Limit
No symbol repeats more than three times consecutively. This is why 4 is IV (not IIII) and 40 is XL (not XXXX). The symbols V, L, and D never repeat because doubling them equals the next symbol up (VV = X, LL = C, DD = M).
How to Convert Numbers to Roman Numerals
Break the number into place values and convert each part. Here are three worked examples:
Example: 276
276 = 200 + 70 + 6
200 = CC, 70 = LXX, 6 = VI
Result: CCLXXVI
Example: 1994
1994 = 1000 + 900 + 90 + 4
1000 = M, 900 = CM, 90 = XC, 4 = IV
Result: MCMXCIV
Example: 3,549
3549 = 3000 + 500 + 40 + 9
3000 = MMM, 500 = D, 40 = XL, 9 = IX
Result: MMMDXLIX
Complete Conversion Chart (1–100)
| 1–10 | 11–20 | 21–30 | Tens |
|---|---|---|---|
| 1 = I | 11 = XI | 21 = XXI | 10 = X |
| 2 = II | 12 = XII | 22 = XXII | 20 = XX |
| 3 = III | 13 = XIII | 23 = XXIII | 30 = XXX |
| 4 = IV | 14 = XIV | 24 = XXIV | 40 = XL |
| 5 = V | 15 = XV | 25 = XXV | 50 = L |
| 6 = VI | 16 = XVI | 26 = XXVI | 60 = LX |
| 7 = VII | 17 = XVII | 27 = XXVII | 70 = LXX |
| 8 = VIII | 18 = XVIII | 28 = XXVIII | 80 = LXXX |
| 9 = IX | 19 = XIX | 29 = XXIX | 90 = XC |
| 10 = X | 20 = XX | 30 = XXX | 100 = C |
Key Years in Roman Numerals
| Year | Roman Numeral | Note |
|---|---|---|
| 1776 | MDCCLXXVI | US Declaration of Independence |
| 1999 | MCMXCIX | One of the longest year representations |
| 2000 | MM | One of the shortest |
| 2024 | MMXXIV | Recent past |
| 2026 | MMXXVI | Current year |
Where Roman Numerals Are Still Used
Despite being largely replaced by Arabic numerals for math and commerce, Roman numerals remain common in specific contexts:
- Super Bowl numbering: The NFL has used Roman numerals since Super Bowl V (1971). Super Bowl LIX was played in February 2025.
- Clock and watch faces: About 80% of analog clock faces use Roman numerals, according to the British Horological Institute. Most use IIII instead of IV — a tradition dating to 14th-century European clockmakers.
- Movie and TV copyright dates: Film studios use Roman numerals in copyright notices (e.g., MMXXVI for 2026).
- Monarchs and popes: King Charles III, Pope Francis (though he has no numeral), Queen Elizabeth II.
- Outlines and lists: Academic papers and legal documents use Roman numerals for hierarchical numbering.
- Building cornerstones: Construction dates are often carved in Roman numerals.
The IIII vs. IV Debate
If you look at a clock, you will likely see IIII instead of IV for 4 o'clock. This is not an error. The convention predates standardized subtractive notation and persists for several proposed reasons: visual balance with VIII on the opposite side, avoiding confusion with VI when read upside down, and pure tradition. The Rolex website confirms they use IIII on all Roman numeral dials.
Roman Numerals Beyond 3,999
Standard Roman numerals max out at 3,999 (MMMCMXCIX). For larger numbers, the vinculum (a bar over the numeral) multiplies the value by 1,000. So V with a bar = 5,000, X with a bar = 10,000, and M with a bar = 1,000,000. This extended notation was used in ancient Rome for large financial and census figures, but it is rarely seen in modern use.
Convert any number to Roman numerals instantly
Use our free Roman Numeral Converter →Frequently Asked Questions
What are the 7 Roman numeral symbols?
The seven basic Roman numeral symbols are: I (1), V (5), X (10), L (50), C (100), D (500), and M (1,000). All Roman numerals are formed by combining these seven symbols using addition and subtraction rules.
What is the largest number you can write in Roman numerals?
Using standard notation (no vinculum or overline), the largest Roman numeral is MMMCMXCIX, which equals 3,999. The system has no symbol for 5,000 or above in standard form. In extended notation, a bar (vinculum) over a numeral multiplies it by 1,000, so V with a bar equals 5,000 and M with a bar equals 1,000,000.
Why is 4 written as IV and not IIII?
The subtractive notation rule says that when a smaller numeral appears before a larger one, you subtract it. IV means 5 minus 1 = 4. This keeps numerals shorter and avoids repeating any symbol more than three times in a row. However, IIII is historically valid and still appears on many clock faces today — a tradition dating back to 14th-century European clockmakers.
How do you convert a large number like 1994 to Roman numerals?
Break the number into place values: 1994 = 1000 + 900 + 90 + 4. Convert each part: 1000 = M, 900 = CM, 90 = XC, 4 = IV. Combine them: MCMXCIV. Always work from largest to smallest value.
Where are Roman numerals still used today?
Roman numerals are commonly used for Super Bowl numbering (e.g., Super Bowl LIX), movie sequel titles, clock and watch faces, book chapter and volume numbers, copyright year notices on films and TV shows, outlines and lists, monarch and pope names (e.g., King Charles III), and building cornerstones. The NFL is the largest annual user of Roman numerals in popular culture.