HesapHanem

Roman Numeral Converter

How do I write Roman numerals?

How it is calculated

Roman numerals use seven letters: I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1000. The tool works through a table of 13 values, the seven letters plus the six subtractive pairs CM = 900, CD = 400, XC = 90, XL = 40, IX = 9 and IV = 4. Starting with the biggest value, it writes the symbol as many times as it fits and subtracts it from the number, then moves to the next. Only whole numbers from 1 to 3999 work, since the standard system has no zero and no symbol beyond M for 4000. Text after the first integer is ignored, and anything outside the range returns an error message.

Worked example

Convert 1994. 1994 − 1000 = 994, write M. 994 − 900 = 94, write CM. 94 − 90 = 4, write XC. 4 − 4 = 0, write IV. Joined together the result is MCMXCIV.

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Common mistakes

  • Entering 0, a negative number or 4000 and above; the standard system covers 1 to 3999 only.
  • Typing a decimal such as 12.9 and expecting rounding; only the integer part before the point is read.
  • Writing 1994 as MDCCCCLXXXXIIII from habit; the correct modern form uses the subtractive pairs: MCMXCIV.
  • Trying to convert a Roman numeral back into a number; this tool goes from number to Roman only.
  • Repeating a symbol four times (IIII, XXXX); the standard form uses IV and XL instead.

About this calculator

This tool converts an ordinary Arabic numeral (1–3999) into Roman numerals using the standard subtractive notation — repeated symbols like III for 3, and subtractive pairs like IV for 4 or IX for 9 — following the same rules the Romans and, later, medieval scribes standardized.

Roman numerals are still used today in specific, mostly ceremonial or stylistic contexts: clock and watch faces, book chapter and outline numbering, movie sequel and Super Bowl numbering, monarch and pope regnal numbers (Elizabeth II, Louis XIV), and copyright dates on film credits. Anyone needing to write one of these correctly uses a converter like this instead of working out the subtraction rules by hand.

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Comments (1)

  • Editorial team

    Year numbers are a common reason to reach for this: 2026 comes out as MMXXVI. One stylistic point is that clock faces traditionally show four o'clock as IIII, while this tool follows the modern subtractive rule and gives IV, so match the convention of whatever you are lettering. Is there a project where you needed Roman numerals, such as a tattoo, a clock, or a chapter list?

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