Roman Numeral Converter
Use this Roman numeral converter to write a number or a year in Roman numerals, or to read a numeral such as MCMLXXXIV back as 1984. Every result comes with a breakdown by place value. The converter checks that a numeral is written in the standard modern form and suggests the correct spelling when it isn't. Turn on extended notation for values up to 3,999,999.
Updated
Results
- Keyboard formFrom 4,000 up: parentheses instead of the bar, (IV) = 4 × 1,000
- BreakdownValue of each place and its Roman letters
| Value | Roman numeral |
|---|
Results are estimates. See the methodology below.
How to use the converter
- Choose a direction: Number → Roman or Roman → number.
- Number → Roman: enter a whole number from 1 to 3,999. To go higher, tick Extended notation; the limit becomes 3,999,999. From 4,000 up, the result also appears in a keyboard-friendly form with parentheses.
- Roman → number: type the numeral in upper or lower case; spaces are ignored. For thousands you can use a bar over the letters or put them in parentheses, as in (IV)DCC.
The breakdown line and the table split the value into thousands, hundreds, tens and ones, and show the Roman letters for each part.
How the converter works
Roman numerals use seven letters:
| I | V | X | L | C | D | M |
|---|---|---|---|---|---|---|
| 1 | 5 | 10 | 50 | 100 | 500 | 1,000 |
A letter after one of greater or equal value adds to it; a letter before a larger one subtracts from it. In the standard form used today, only I, X and C are subtracted, and only from the next two larger letters: IV (4), IX (9), XL (40), XC (90), CD (400) and CM (900). V, L and D are never subtracted, and no letter appears more than three times in a row.
The converter writes each decimal place separately and joins the parts, which gives exactly one standard spelling for every number from 1 to 3,999. When you convert a numeral back, it computes the value and then compares your input with the standard spelling of that value. If they differ, it shows the standard form instead of guessing.
Extended notation. A bar over a numeral multiplies it by 1,000. From 4,000 up, the converter writes the thousands with a bar and the rest normally. Below 4,000 it keeps the standard form, so 3,888 stays MMMDCCCLXXXVIII.
Worked examples
1. Years
| Year | Roman numeral | Breakdown |
|---|---|---|
| 2026 | MMXXVI | MM + XX + VI |
| 1994 | MCMXCIV | M + CM + XC + IV |
| 1964 | MCMLXIV | M + CM + LX + IV |
The largest standard numeral is 3,999 = MMMCMXCIX. Super Bowl LX is number 60.
2. Large numbers
With extended notation, 4,700 is I̅V̅DCC, or (IV)DCC in keyboard form, and 12,345 is X̅I̅I̅CCCXLV, or (XII)CCCXLV. Its breakdown reads 10,000 + 2,000 + 300 + 40 + 5.
3. Reading a numeral
MCMLXXXIV converts to 1984: 1,000 + 900 + 80 + 4. If you type IIII, the converter reports that the standard form of 4 is IV. IC is flagged too: 99 is written XCIX.
About the strict check
The checking follows the modern standard form. Some clock dials and some style guides do not always follow it, so a rejected numeral is not necessarily "wrong" in its original setting; it simply has a different standard spelling today. Bars may look slightly off in some fonts; the parentheses form avoids that.
Frequently asked questions
Why does the converter stop at 3,999 without extended notation?
Because no letter may repeat more than three times, MMMCMXCIX (3,999) is the largest value you can write with the seven basic letters. The Canadian government's Language Portal allows M to repeat, as in MMMM. This converter is stricter: for 4,000 it suggests I̅V̅ with extended notation.
What does a bar over a Roman numeral mean?
It multiplies the value by 1,000, so V̅ is 5,000 and M̅ is 1,000,000. Both the Language Portal and the U.S. Government Printing Office Style Manual describe this rule. The converter uses it up to 3,999,999, written M̅M̅M̅C̅M̅X̅C̅I̅X̅CMXCIX.
Why do some clocks show IIII instead of IV?
IIII appears on some clock dials, as the Language Portal notes. It is not the modern standard form, so the converter answers IIII with the suggestion IV. Both are read as 4.
Why isn't 99 written IC?
In standard notation, I can be subtracted only from V and X, X only from L and C, and C only from D and M. So 99 is 90 + 9 = XC + IX = XCIX. For the same reason 49 is XLIX, not IL.
How do I write this year or next year in Roman numerals?
2026 is MMXXVI: two thousands (MM), two tens (XX) and six (VI). 2027 is MMXXVII. Years are still written in Roman numerals in some formal contexts, such as 1964 = MCMLXIV.
Is there a Roman numeral for zero or for negative numbers?
None of the seven standard letters stands for zero, and this converter accepts only whole numbers from 1 upward. Negative numbers and fractions are not supported.
Sources
This converter follows the modern standard form of Roman numerals. Historical and decorative uses may follow other conventions.