Convert numbers between decimal format and Roman numerals. Roman numerals were used in ancient Rome and can still be seen in modern times.
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Convert numbers to Roman numerals and Roman numerals back to numbers. Type a value in either box and the other updates instantly. The converter covers the standard range 1 to 3,999, which is everything classical Roman numerals can express without special overline notation.
Roman numerals still appear on clock faces, book chapters, film copyright dates, monarch and pope names, the Super Bowl, building cornerstones and outline numbering. Reading them comes down to seven letters and one rule about subtraction.
I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1000Symbols are added left to right when a larger or equal value comes first: VI = 6, XXVII = 27A smaller value before a larger one is subtracted: IV = 4, IX = 9, XL = 40, CM = 900Only I, X and C are used as subtractors, and only before the next two larger symbolsNo symbol repeats more than three times in a row: 4 is IV, never IIIIThere is no zero and no negative numbers2000 = MM, 20 = XX, 6 = VI. Put together: MMXXVI.
1000 = M, 900 = CM, 90 = XC, 4 = IV. This year appears in a lot of film credits: MCMXCIV.
XL = 40 (10 before 50), II = 2. Total 42 — as in the Super Bowl and Douglas Adams.
You cannot subtract I from L directly. 49 is built as 40 (XL) + 9 (IX) = XLIX.
The longest numeral under 4000: MMM + DCCC + LXXX + VIII, 15 characters.
The Roman system is additive and had no need for a placeholder digit. When Roman scholars needed "nothing" they wrote the Latin word nulla.
With standard letters, 3,999 (MMMCMXCIX). Larger numbers historically used a bar over a letter to multiply it by 1,000, which most modern uses avoid.
Standard modern usage is IV. IIII still appears on many clock faces by tradition, for visual balance opposite VIII.
No. Only I before V or X, X before L or C, and C before D or M. So 99 is XCIX, not IC.
Conventionally Roman numerals are written in capitals. This converter accepts lower case and normalises it.
Break it into thousands, hundreds, tens and units from the left: MM (2000), X X (20), VI (6) = 2026.