Roman numeral converter
Type a number or a Roman numeral and get the conversion instantly. If the numeral is not valid, we explain why and show you the correct form.
Type a number (1994) or a Roman numeral (MCMXCIV). We detect which one it is.
From 1 to 3999
| Letter | Value |
|---|---|
| I | 1 |
| V | 5 |
| X | 10 |
| L | 50 |
| C | 100 |
| D | 500 |
| M | 1000 |
- Add from largest to smallest: XVI = 10 + 5 + 1 = 16. I, X, C, and M repeat up to three times; V, L, and D never do.
- Subtract when a smaller letter comes first: IV = 4, IX = 9, XL = 40, XC = 90, CD = 400, CM = 900. There are no other subtractions.
- Large thousands get a bar on top: V̅ = 5000. Without a bar, the maximum is MMMCMXCIX = 3999.
Clocks often show IIII instead of IV; both forms are understood.
How to use it
- Type a number (for example, 1994) or a Roman numeral (for example, MCMXCIV). The tool detects which one it is.
- Read the result and its breakdown, letter by letter, to see how it is built.
- If you typed an incorrect numeral such as IC or VX, read the explanation and use the correct form we suggest.
- Use the tabs to turn a date into Roman numerals, generate a list from 1 to N, or look up the table of values.
Frequently asked questions
Why is there no zero in Roman numerals?
The Roman system was built to count and record quantities, and it had no symbol for zero. Medieval texts used the Latin word “nulla” when they needed one. That is why the first Roman numeral is I.
How do you write 4: IV or IIII?
The usual form is IV. IIII shows up on many clocks and in some old inscriptions. The converter accepts it and tells you the standard form.
What is the largest Roman numeral?
In the standard form it is MMMCMXCIX (3999). For larger numbers, a bar goes over the letters and multiplies their value by a thousand: I̅V̅ is 4000. Turning on “Large numbers” takes you up to 3,999,999. The bar may not display in every font, so we also offer parentheses notation.
Why is IC not 99?
Subtraction has rules: I can only be subtracted from V and X, X from L and C, and C from D and M. So 99 is written XCIX (XC plus IX), not IC. The same goes for VX, IL, XM, and similar combinations.
How do I write the current year and a full date?
The current year is one click away with “Current year.” In the Date tab you pick the day and get, for example, IX-XXIX-MMXXVI for September 29, 2026, with the century included.
Can I type in lowercase?
Yes. You can type the numeral in lowercase (mcmxciv) and also get the result in lowercase with the “Lowercase result” checkbox. Roman numerals are normally written in capital letters.
How Roman numerals are formed
Seven letters are used: I (1), V (5), X (10), L (50), C (100), D (500), and M (1000). Values are added from largest to smallest (XVI is 16). When a smaller letter comes before a larger one, it is subtracted: IV is 4 and IX is 9.
- Repetition: I, X, C, and M can repeat up to three times in a row. V, L, and D never repeat.
- Valid subtractions: only IV, IX, XL, XC, CD, and CM.
- No zero and no negatives: the system only writes positive whole numbers.
Where they are used today
You see them in book chapters, centuries (the XXI century), the acts of a play, the names of kings and popes (Pope John Paul II), clock faces, and the editions of events such as the Super Bowl. Years and dates are also written this way on plaques and monuments.
Updated on September 29, 2026