Roman Numerals Validator and Converter to Numbers, Online

Validate and convert Roman numerals to Hindu-Arabic numbers

Learn how to convert Roman numerals to Hindu-Arabic numbers: - [+] - Identify and calculate the value of each group of numerals written in subtractive notation. - [+] - Calculate the Hindu-Arabic number: add up all the values of the individual Roman numerals (written in additive notation) and of the groups of numerals written in subtractive notation.

The latest Roman numerals validated and converted to Hindu-Arabic numbers

Is the Roman numeral CCX valid or not? How to convert it, how to write it as a Hindu-Arabic number? Roman numerals (numbers) validator Jan 22 16:10 UTC (GMT)
Is the Roman numeral MMX valid or not? How to convert it, how to write it as a Hindu-Arabic number? Roman numerals (numbers) validator Jan 22 16:09 UTC (GMT)
Is the Roman numeral (L)(V)MMMCLXXXIV valid or not? How to convert it, how to write it as a Hindu-Arabic number? Roman numerals (numbers) validator Jan 22 16:09 UTC (GMT)
Is the Roman numeral (V)MMLXV valid or not? How to convert it, how to write it as a Hindu-Arabic number? Roman numerals (numbers) validator Jan 22 16:09 UTC (GMT)
Is the Roman numeral CXXVIII valid or not? How to convert it, how to write it as a Hindu-Arabic number? Roman numerals (numbers) validator Jan 22 16:08 UTC (GMT)
Is the Roman numeral (V)MMCCXXIII valid or not? How to convert it, how to write it as a Hindu-Arabic number? Roman numerals (numbers) validator Jan 22 16:08 UTC (GMT)
Is the Roman numeral CCCXX valid or not? How to convert it, how to write it as a Hindu-Arabic number? Roman numerals (numbers) validator Jan 22 16:08 UTC (GMT)
Is the Roman numeral (C)MDCCCXIII valid or not? How to convert it, how to write it as a Hindu-Arabic number? Roman numerals (numbers) validator Jan 22 16:07 UTC (GMT)
Is the Roman numeral (C)(C)(L)MXLIII valid or not? How to convert it, how to write it as a Hindu-Arabic number? Roman numerals (numbers) validator Jan 22 16:07 UTC (GMT)
Is the Roman numeral MX valid or not? How to convert it, how to write it as a Hindu-Arabic number? Roman numerals (numbers) validator Jan 22 16:07 UTC (GMT)
Is the Roman numeral MDCCCXCIX valid or not? How to convert it, how to write it as a Hindu-Arabic number? Roman numerals (numbers) validator Jan 22 16:07 UTC (GMT)
Is the Roman numeral CXXXII valid or not? How to convert it, how to write it as a Hindu-Arabic number? Roman numerals (numbers) validator Jan 22 16:06 UTC (GMT)
Is the Roman numeral CXIII valid or not? How to convert it, how to write it as a Hindu-Arabic number? Roman numerals (numbers) validator Jan 22 16:06 UTC (GMT)
» New: Calculations Performed by Our Visitors: Numbers written with Roman numerals validated and converted to Hindu-Arabic numbers. Data organized on a Monthly Basis

The set of basic symbols of the Roman system of writing numerals

The major set of symbols on which the rest of the Roman numberals were built:

  • I = 1 (one); V = 5 (five);

  • X = 10 (ten); L = 50 (fifty);

  • C = 100 (one hundred);

  • D = 500 (five hundred);

  • M = 1,000 (one thousand);

For larger numbers:

  • (*) V = 5,000 or |V| = 5,000 (five thousand); see below why we prefer this notation: (V) = 5,000.

  • (*) X = 10,000 or |X| = 10,000 (ten thousand); see below why we prefer this notation: (X) = 10,000.

  • (*) L = 50,000 or |L| = 50,000 (fifty thousand); see below why we prefer this notation: (L) = 50,000.

  • (*) C = 100,000 or |C| = 100,000 (one hundred thousand); see below why we prefer this notation: (C) = 100,000.

  • (*) D = 500,000 or |D| = 500,000 (five hundred thousand); see below why we prefer this notation: (D) = 500,000.

  • (*) M = 1,000,000 or |M| = 1,000,000 (one million); see below why we prefer this notation: (M) = 1,000,000.

(*) These numbers were written with an overline (a bar above) or between two vertical lines. Instead, we prefer to write these larger numerals between brackets, ie: "(" and ")", because:

  • 1) when compared to the overline - it is easier for the computer users to add brackets around a letter than to add the overline to it and
  • 2) when compared to the vertical lines - it avoids any possible confusion between the vertical line "|" and the Roman numeral "I" (1).

(*) An overline (a bar over the symbol), two vertical lines or two brackets around the symbol indicate "1,000 times". See below...

Logic of the numerals written between brackets, ie: (L) = 50,000; the rule is that the initial numeral, in our case, L, was multiplied by 1,000: L = 50 => (L) = 50 × 1,000 = 50,000. Simple.

(*) At the beginning Romans did not use numbers larger than 3,999; as a result they had no symbols in their system for these larger numbers, they were added on later and for them various different notations were used, not necessarily the ones we've just seen above.

Thus, initially, the largest number that could be written using Roman numerals was:

  • MMMCMXCIX = 3,999.