Date to Roman Numerals Calculator
Writing a date in Roman numerals is a tradition you see on cornerstones, monuments, clock faces, and film copyright lines. This calculator converts each part of a date, the day, the month number, and the year, into Roman numerals using the standard subtractive notation, where IV is 4 and IX is 9, built from the seven letters I, V, X, L, C, D, and M. It shows the three parts separately and combined, so you can use whichever form you need. Because the basic letters reach only 3,999, the year is limited to that range, and there is no symbol for zero.
Roman numeral conversion
I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1000
subtractive pairs: IV = 4, IX = 9, XL = 40, XC = 90, CD = 400, CM = 900
greedily subtract the largest value that fits, appending its symbol
convert day, month, and year separately, then join
The algorithm repeatedly takes the largest numeral value that does not exceed the remaining number, writes its symbol, and subtracts it, until the number reaches zero. This produces the standard modern form used on monuments and in copyright dates.
Roman numeral notes
- The seven letters are I, V, X, L, C, D, and M.
- A smaller numeral before a larger one is subtracted, as in IV and IX.
- There is no Roman numeral for zero.
- Basic letters reach a maximum of 3,999 (MMMCMXCIX).
- The year 2026 is MMXXVI; the month June (6) is VI.
Date to Roman numerals: frequently asked questions
How are Roman numerals formed?
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 1000. Values are written largest to smallest and added together, with a subtractive rule where a smaller numeral before a larger one is subtracted, such as IV for 4 and IX for 9.
How is a date written in Roman numerals?
Each part of the date, the day, the month number, and the year, is converted separately into Roman numerals. The calculator shows all three and joins them with separators, for example 17 June 2026 becomes XVII for the day, VI for the month, and MMXXVI for the year.
Why is there no Roman numeral for zero?
The Roman system has no symbol for zero because it was designed for counting and recording quantities rather than positional arithmetic. That is why Roman numerals start at I for one, and why this calculator only converts values of 1 and above.
What is the largest year this handles?
Standard Roman numerals using the seven basic letters represent values up to 3,999, written MMMCMXCIX. Beyond that, ancient writers used bars over letters to multiply by a thousand, a notation this calculator does not produce, so it limits the year to 3,999.
Where are Roman numeral dates used today?
They commonly appear on cornerstones of buildings, in film and television copyright lines, on monuments, clock faces, and in the names of monarchs and popes. Writing a date in Roman numerals is mostly decorative or traditional rather than practical.
Official sources
- International Organization for Standardization: ISO 8601 date and time format.
- National Institute of Standards and Technology: NIST home.
Reviewed by the CalculatorHub team, edited by James Graham, 17 June 2026. See our methodology.