Roman Numeral Converter

About Roman Numerals

Roman numerals are a numeral system that originated in ancient Rome and remained the usual way of writing numbers throughout Europe well into the Late Middle Ages. Numbers in this system are represented by combinations of letters from the Latin alphabet.

How Roman Numerals Work

Roman numerals use the following symbols with corresponding values:

• I = 1
• V = 5
• X = 10
• L = 50
• C = 100
• D = 500
• M = 1000

Numbers are formed by combining these letters and adding their values. A letter placed after another of greater value adds (e.g., VI = 5 + 1 = 6), while a letter placed before another of greater value subtracts (e.g., IV = 5 - 1 = 4).

Rules for Roman Numerals

There are specific rules for forming Roman numerals:

• When a symbol appears after a larger symbol, it is added (e.g., VI = 5 + 1 = 6)
• When a symbol appears before a larger symbol, it is subtracted (e.g., IX = 10 - 1 = 9)
• The same symbol cannot be used more than three times in a row (e.g., III = 3 is valid, but IIII is not valid for 4)
• Only I, X, and C can be used as subtractive numerals (e.g., VX is not a valid way to write 5)
• A bar placed over a numeral multiplies its value by 1,000 (e.g., V̅ = 5,000)

Modern Uses of Roman Numerals

While Roman numerals are not used for calculations today, they still appear in several contexts:

• Clock faces (e.g., IIII or IV for 4 o'clock)
• Book chapters and volume numbers
• Movie release years and sequels
• Monarch and pope names (e.g., Elizabeth II)
• Building construction dates
• Sporting events (e.g., Super Bowl LVII)

Limitations of Roman Numerals

The Roman numeral system has several limitations that led to its replacement by the Hindu-Arabic numeral system:

• No symbol for zero
• Difficult to perform arithmetic operations
• Cumbersome for large numbers
• Ambiguity in some representations (e.g., IIII vs IV for 4)