How do I write my birthday in Roman numerals?

Convert the three fields separately and join them. Take 9 August 2015: the day 9 is IX, the month 8 is VIII, and the year 2015 is MMXV, so day-first the date is IX·VIII·MMXV. Do not run the digits together and convert 9,082,015 as one number - that is the single most common mistake and it produces a long meaningless string. Nothing is padded either, so a single-digit day stays one letter: the ninth is IX, never 09 or 0IX. The Date tab on the converter does all three pieces at once and shows the value of each, which is the quickest way to check a result before you commit to it.

Should the day or the month come first?

Either - the numerals do not encode an order, so it is a choice you make and one a reader cannot recover from the letters alone. Day · month · year is the most common on tattoos and the norm outside the United States; month · day · year is the American reading order; year · month · day is usual on buildings and formal inscriptions. The one thing worth checking is whether your date is ambiguous: if both small numbers are 12 or under, as in VIII·III·MCMXCIX, it reads as two different real dates depending on the order, and there is no way to tell them apart later. A day above the twelfth removes the ambiguity by itself.

Is four written IV or IIII, and is there a numeral for zero?

Use IV for a date. IV is the standard subtractive spelling; IIII is the older additive form and is not exactly wrong, but it survives mainly on clock and watch faces, where it balances the VIII opposite it on the dial. There is no numeral for zero at all - the system has no symbol for it, which is why dates are never padded and the fifth of the month is V rather than 0V. Roman arithmetic also had no way to write a negative number or a fraction, so a converter that offers you a zero or a decimal is inventing notation rather than reporting it.

How to Write a Date in Roman Numerals

A date in Roman numerals is three numerals standing side by side, not one long number. That single fact is behind nearly every mistake that ends up on a tattoo, a wedding invitation, a cornerstone or a film credit. Get it right and the rest is mechanical: convert the day, convert the month, convert the year, join them with a separator you like. This guide walks through each step, the choices worth making deliberately, and the errors that are expensive to discover late. Everything here can be checked against the Roman Numeral Converter, whose Date tab writes all three pieces at once.

Three numerals, not one number

The most common error is to treat the date as a single figure. 25 December 1990 is not 25,121,990, and converting that number gives a long, meaningless string of letters. Each field is converted on its own and the three results are placed in a row: 25 becomes XXV, 12 becomes XII, 1990 becomes MCMXC, and the date is XXV·XII·MCMXC.

This is also why a numeral date needs a separator in a way an ordinary date does not. Roman numerals have no fixed width, so without something between them the letters run together into one numeral that reads as a completely different value. The separator is not decoration - it is what tells a reader where the day ends and the month begins.

The seven letters and the two rules

Everything is built from seven letters:

I is 1, V is 5, X is 10, L is 50.
C is 100, D is 500, M is 1,000.

Letters are written largest first and added up, so XXV is 10 + 10 + 5 = 25. The exception is subtraction: a smaller letter placed in front of a larger one is taken away instead. There are exactly six of these, and no others are standard - IV (4), IX (9), XL (40), XC (90), CD (400) and CM (900). Two further limits keep spellings honest: I, X, C and M may repeat up to three times in a row, while V, L and D are never repeated, because two of them simply make the next letter up.

A worked example: 25 December 1990

Take the three fields one at a time.

Day, 25: the largest letter that fits is X, twice, leaving 5, which is V. That gives XX + V = XXV.
Month, 12: X leaves 2, written II. That gives XII.
Year, 1990: M covers 1,000 and leaves 990. The next 900 is not written with nine Cs but as CM, one hundred taken from one thousand. That leaves 90, which is XC by the same logic. The year is M + CM + XC = MCMXC.

Read MCMXC back and the arithmetic is 1,000 + (1,000 - 100) + (100 - 10) = 1,990. Joined with middle dots the finished date is XXV·XII·MCMXC. Paste it into the Roman Numeral Converter and it will take the date apart the same way, showing the value of each piece.

A second example: 14 February 2026 is XIV·II·MMXXVI, where the year is 1,000 + 1,000 + 10 + 10 + 5 + 1. Years in the 2000s come out noticeably shorter than years in the 1900s, which is worth knowing if you are choosing between two dates for a design.

Choosing the order and the separator

Nothing in the numerals themselves fixes the field order, so it is your choice - but make it a deliberate one, because a reader cannot recover it from the letters. The three orders in ordinary use each give a different result for the same day:

Day · month · year - XXV·XII·MCMXC. The usual choice outside the United States, and the most common on tattoos.
Month · day · year - XII·XXV·MCMXC. The American reading order.
Year · month · day - MCMXC·XII·XXV. Used on buildings and in formal inscriptions, where the year is the point.

For the separator, a middle dot is the conventional choice for a tattoo or an engraving and keeps the fields visually distinct. A full stop, a slash, an en dash or a plain space all appear and are equally readable. The converter offers all five so you can see the same date in each before committing to one.

There is no leading zero, and no zero at all

Roman numerals have no symbol for zero, so nothing is ever padded to two digits. The fifth of the month is V, not 0V; January is I, not 0I. A date written 0V·0I·MMXX is not a stricter version of 5 January 2020 - it is not a Roman numeral at all, because the character 0 does not exist in the system. This trips people up because the digital habit of writing 05/01/2020 is so strong.

Roman counting had no zero, no negative numbers and no fractions of a unit, which is why a numeral clock face starts at I and why medieval scribes writing in Latin used the word nulla when they needed to record nothing at all.

IV or IIII

Both are read as four, and neither is a misprint. IV is the standard subtractive spelling and the one to use for a date. IIII is the older additive form, and it survives in one very visible place: the great majority of clock and watch faces use IIII rather than IV, because it balances the VIII directly opposite it on the dial. If you want a numeral to look like a clock face, IIII is defensible. For a date, use IV - a converter, a proofreader or a relative will otherwise read it as an error.

The Roman Numeral Converter takes the middle position here: type IIII and it still returns 4, then tells you the standard spelling is IV and why. That matters when you are reading a numeral off an old inscription rather than writing a new one, since historical numerals break the modern rules constantly.

Reading a numeral date back, and why it can be ambiguous

Going the other way is mechanical, with one catch. When both small numbers are 12 or under, nothing in the numerals says which is the day and which is the month. VIII·III·MCMXCIX is 8 March 1999 read day-first and 3 August 1999 read month-first, and both are real dates. The converter reports every field order that yields a valid date rather than silently picking one, so you can see the ambiguity instead of inheriting it.

XXV·XII·MCMXC has no such problem: 25 cannot be a month, so the order is settled by arithmetic. If you have a choice of dates and want one that reads unambiguously, a day above the twelfth does it.

Dates that never happened

A converter that only checks the day against 31 will happily write 29·II·MCM for you. February 1900 had 28 days: 1900 is divisible by 100 and not by 400, so it was not a leap year under the Gregorian rule, and that date does not exist. The Date tab checks the day against its actual month and year and refuses the impossible ones, which is a check worth having before a date is cut into stone or skin.

It all runs in your browser

Birthdays, wedding dates and anniversaries are personal, and there is no reason a converter should see them. Every conversion here is worked out in JavaScript inside your browser tab - nothing is uploaded and there is no signup. The same tool converts in both directions, and the Number to Words converter spells a figure out in English when that is what you need.

Frequently asked questions

How do I write my birthday in Roman numerals?: Convert the three fields separately and join them. Take 9 August 2015: the day 9 is IX, the month 8 is VIII, and the year 2015 is MMXV, so day-first the date is IX·VIII·MMXV. Do not run the digits together and convert 9,082,015 as one number - that is the single most common mistake and it produces a long meaningless string. Nothing is padded either, so a single-digit day stays one letter: the ninth is IX, never 09 or 0IX. The Date tab on the converter does all three pieces at once and shows the value of each, which is the quickest way to check a result before you commit to it.
Should the day or the month come first?: Either - the numerals do not encode an order, so it is a choice you make and one a reader cannot recover from the letters alone. Day · month · year is the most common on tattoos and the norm outside the United States; month · day · year is the American reading order; year · month · day is usual on buildings and formal inscriptions. The one thing worth checking is whether your date is ambiguous: if both small numbers are 12 or under, as in VIII·III·MCMXCIX, it reads as two different real dates depending on the order, and there is no way to tell them apart later. A day above the twelfth removes the ambiguity by itself.
Is four written IV or IIII, and is there a numeral for zero?: Use IV for a date. IV is the standard subtractive spelling; IIII is the older additive form and is not exactly wrong, but it survives mainly on clock and watch faces, where it balances the VIII opposite it on the dial. There is no numeral for zero at all - the system has no symbol for it, which is why dates are never padded and the fifth of the month is V rather than 0V. Roman arithmetic also had no way to write a negative number or a fraction, so a converter that offers you a zero or a decimal is inventing notation rather than reporting it.