Convert numbers to Roman numerals and Roman numerals back to numbers. Supports values from 1 to 3,999.
Basic symbols: I=1, V=5, X=10, L=50, C=100, D=500, M=1000.
Addition rule: Symbols are added left to right. VI = 5+1 = 6. XVII = 10+5+1+1 = 17.
Subtraction rule: A smaller symbol before a larger one means subtract. IV = 5-1 = 4. IX = 10-1 = 9. XL = 50-10 = 40. XC = 100-10 = 90. CD = 500-100 = 400. CM = 1000-100 = 900.
Roman numerals originated in ancient Rome and were the dominant number system in Europe for nearly two thousand years. The system likely evolved from tally marks used by shepherds to count livestock. The symbols I, V, and X may have originated from hand gestures: I for a single finger, V for an open hand (five fingers), and X for two crossed hands (ten). The higher symbols L, C, D, and M developed later as the Roman Empire grew and needed to represent larger quantities for census data, military records, and construction projects.
Despite being largely replaced by Hindu-Arabic numerals (our current 0-9 system) starting around the 14th century, Roman numerals remain in widespread use today. You see them on clock faces, in movie sequel titles (Rocky IV), for Super Bowl numbering (Super Bowl LVIII), in book chapter headings, on building cornerstones to indicate the year of construction, and in formal outlines (I, II, III). The copyright dates at the end of movies and TV shows traditionally use Roman numerals. Popes and monarchs use Roman numerals for their regnal numbers (Queen Elizabeth II, Pope Francis I).
The standard Roman numeral system can only represent numbers from 1 to 3,999 (MMMCMXCIX). Ancient Romans used an overline notation (a bar above a symbol) to multiply by 1,000, allowing representation of larger numbers, but this extended system is rarely used today. The system also has no symbol for zero, which was one of the key innovations of the Hindu-Arabic system that ultimately made it superior for mathematics and commerce.
| Number | Roman | Number | Roman |
|---|---|---|---|
| 1 | I | 50 | L |
| 4 | IV | 90 | XC |
| 5 | V | 100 | C |
| 9 | IX | 400 | CD |
| 10 | X | 500 | D |
| 40 | XL | 900 | CM |
| 2024 | MMXXIV | 1000 | M |
2024 in Roman numerals is MMXXIV. M=1000, M=1000, X=10, X=10, IV=4. Total: 1000+1000+10+10+4 = 2024.
In the standard system, the largest number is 3,999 (MMMCMXCIX). M is the largest single symbol at 1,000. Numbers above 3,999 required an overline notation in ancient times.
No. Roman numerals have no symbol for zero. The concept of zero as a number was developed in India and was one of the key advantages of the Hindu-Arabic numeral system.
This is called the "watchmaker's four." The most common theory is visual balance -- IIII on the left side of the clock face mirrors VIII on the right. Another theory is that it avoids confusion with IV (Jupiter in Latin, which was disrespectful to place on timepieces).