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FromRomanNumeral["string"]

gives the integer corresponding to the Roman numeral "string".

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FromRomanNumeral

FromRomanNumeral["string"]

gives the integer corresponding to the Roman numeral "string".

Details

  • Numerals can be specified with either upper- or lowercase characters.

Examples

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Basic Examples  (2)

Convert a Roman numeral into a decimal integer:

Wolfram Language code: FromRomanNumeral["MCMXXXVII"]

Convert a list of Roman numerals into respective decimal integers:

Wolfram Language code: FromRomanNumeral[{"i", "ii", "iii", "iv", "v", "vi", "vii", "viii"}]

Scope  (3)

Roman numerals can be given in upper case, in lower case, or a mixture of both:

Wolfram Language code: FromRomanNumeral["MMXV"]
Wolfram Language code: FromRomanNumeral["mmxv"]
Wolfram Language code: FromRomanNumeral["MMxv"]

The numeral "N" represents the integer 0:

Wolfram Language code: FromRomanNumeral["N"]

FromRomanNumeral threads automatically over lists of numerals:

Wolfram Language code: FromRomanNumeral[{"ci", "cii", "ciii", "civ", "cv", "cvi", "cvii", "cviii"}]

Properties & Relations  (2)

RomanNumeral converts a decimal integer into its Roman numeral form:

Wolfram Language code: RomanNumeral[1234]
Wolfram Language code: FromRomanNumeral[%]

FromRomanNumeral["string"] is equivalent to FromDigits["string","Roman"]:

Wolfram Language code: FromRomanNumeral["MMMDCCXLVIII"]
Wolfram Language code: FromDigits["MMMDCCXLVIII", "Roman"]

Possible Issues  (1)

FromRomanNumeral can interpret nonstandard forms of Roman numerals:

Wolfram Language code: FromRomanNumeral["xcix"]
Wolfram Language code: FromRomanNumeral[{"ic", "lil", "lxxxxix", "xxxxxxxxxix", "xxxxxxxxxiiiiiiiii"}]

In fact, any combination of valid digits is interpreted as an integer:

Wolfram Language code: digits = {"I", "V", "X", "L", "C", "D", "M"}
Wolfram Language code: StringJoin[RandomChoice[digits, 6]]
Wolfram Language code: FromRomanNumeral[%]

To check whether a given roman numeral is written in canonical form, compare to the output of RomanNumeral:

Wolfram Language code: RomanNumeral[%]
Wolfram Research (2015), FromRomanNumeral, Wolfram Language function, https://reference.wolfram.com/language/ref/FromRomanNumeral.html.

Text

Wolfram Research (2015), FromRomanNumeral, Wolfram Language function, https://reference.wolfram.com/language/ref/FromRomanNumeral.html.

CMS

Wolfram Language. 2015. "FromRomanNumeral." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/FromRomanNumeral.html.

APA

Wolfram Language. (2015). FromRomanNumeral. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/FromRomanNumeral.html

BibTeX

@misc{reference.wolfram_2026_fromromannumeral, author="Wolfram Research", title="{FromRomanNumeral}", year="2015", howpublished="\url{https://reference.wolfram.com/language/ref/FromRomanNumeral.html}", note=[Accessed: 12-June-2026]}

BibLaTeX

@online{reference.wolfram_2026_fromromannumeral, organization={Wolfram Research}, title={FromRomanNumeral}, year={2015}, url={https://reference.wolfram.com/language/ref/FromRomanNumeral.html}, note=[Accessed: 12-June-2026]}