Roman Numeral Converter: Numbers to Roman Numerals and Back
Turn a year or any whole number up to 3,999 into Roman numerals, or type a numeral such as MCMLXXXIV to read its value, with a note when a numeral is not written the standard way.
Roman numerals use seven letters: I is 1, V is 5, X is 10, L is 50, C is 100, D is 500 and M is 1,000. A letter after a larger one adds to it and a letter before a larger one subtracts, so IV is 4 and VI is 6. 2026 is MM (2,000) plus XX (20) plus VI (6), written MMXXVI.
This converter writes and reads Roman numerals in your browser following the add-and-subtract rule in the GPO Style Manual (2016). It covers whole numbers from 1 to 3,999 and does not read the bar used for larger values. If a numeral will be carved, engraved or tattooed, check it against the standard form shown here before it is made.
Roman numeral
MMXXVI
MM = 2,000, XX = 20, VI = 6
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About the Roman Numeral Converter
The reading rule here is the one in the U.S. Government Publishing Office Style Manual (2016), rule 12.29: a repeated letter repeats its value, a letter placed after one of greater value adds to it, and a letter placed before one of greater value subtracts from it. Written out, a number is built one place at a time, thousands first, then hundreds, tens and ones, and the result shows each part so you can check it. The standard form uses six subtractive pairs: IV (4), IX (9), XL (40), XC (90), CD (400) and CM (900). That is why 1984 is MCMLXXXIV, M for 1,000, CM for 900, LXXX for 80 and IV for 4. The converter writes numbers from 1 to 3,999. Above that, Roman practice puts a bar over a letter to multiply it by 1,000, which plain text cannot show reliably, and there is no numeral for 0, for negative numbers or for fractions. Reading works on any string of the seven letters, in capitals or lower case. Older and looser forms still read correctly, such as IIII on clock faces (4) or MDCCCC for 1900, and the result points out the standard spelling. A letter that is not one of the seven is named along with its position.
Frequently asked questions
Why does a clock show IIII instead of IV?+
Many clock and watch faces use IIII for 4 by tradition, and it reads correctly under the add-and-subtract rule. It is not the standard form, though, so if you type IIII here the converter returns 4 and notes that the standard spelling is IV.
What is the largest number I can write in Roman numerals?+
With the seven plain letters, the largest standard numeral is MMMCMXCIX, 3,999. For larger values, a bar over a letter multiplies it by 1,000. The GPO table gives 4,000 as MMMM or as M followed by a barred V. This converter writes up to 3,999 and reads MMMM as 4,000, but it does not read or write the bar.
Is IC a correct way to write 99?+
It appears in the GPO Style Manual's own table, and by the subtraction rule it equals 99. The usual standard form is XCIX, ninety (XC) plus nine (IX). Since the converter writes only the six standard pairs, it writes XCIX and reads IC as 99 with a note.
How do I write a year in Roman numerals?+
Enter the year as a number. 1990 becomes MCMXC, 2000 is MM and 2026 is MMXXVI. Film credits and building cornerstones often use this, and the breakdown under the result shows which letters stand for the thousands, hundreds, tens and ones.
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