Roman Numerals Converter

How to use the Roman numeral converter

Type an ordinary number in the Number box to see it in Roman numerals, or type a numeral in the Roman numeral box to see its value — the other box fills in automatically. Lowercase letters are fine. Below the answer you get the numeral split into its place-value groups and the steps used to build or read it. If a numeral breaks the standard rules, the converter explains which rule and offers the correct form. The page address updates as you type, so you can bookmark or share a conversion.

The seven symbols and the rules

• Add when a symbol is followed by one of equal or smaller value: VI = 5 + 1 = 6, XX = 20, MD = 1,500.
• Subtract when a smaller symbol comes before a larger one — but only in six pairs: IV (4), IX (9), XL (40), XC (90), CD (400) and CM (900).
• Repeat I, X, C and M at most three times in a row. V, L and D are never repeated and never subtracted.
• Write each place value once, largest first: thousands, then hundreds, tens and ones. Each decimal digit maps to exactly one pattern, which is why every number from 1 to 3,999 has one standard spelling.

Worked examples

1994 to Roman numerals. Split the number by place value: 1994 = 1000 + 900 + 90 + 4. Convert each part: 1000 = M, 900 = CM (1000 − 100), 90 = XC (100 − 10) and 4 = IV (5 − 1). Join them in order: M + CM + XC + IV = MCMXCIV.

MMXXVI to a number. Group the letters by place value: MM | XX | VI. MM = 1000 + 1000 = 2000, XX = 10 + 10 = 20 and VI = 5 + 1 = 6. Add the groups: 2000 + 20 + 6 = 2026.

Why some numerals are rejected

Many letter strings can be “read” by adding and subtracting, but only one of them is the standard form. The converter checks the standard form strictly and tells you what is wrong:

• IIII — a symbol is used at most three times, so 4 is IV.
• VX or VV — V, L and D only ever add, and VV would just be X.
• IC, IL or XM — I, X and C can only be subtracted from the next two larger symbols, so 99 is XCIX.
• IIX — only one smaller symbol may stand before a larger one; 8 is VIII.
• XCX — the tens place is written twice; 100 is simply C.

These rules are a later standardization. Roman inscriptions are not always consistent, and IIII is still common on clock faces. If you are transcribing an old date that uses a variant, the converter’s suggestion shows the value the variant most likely means.

Numbers above 3,999: the vinculum

Standard Roman numerals stop at 3,999 (MMMCMXCIX). For larger values, one common medieval convention draws a bar — a vinculum — over a numeral to multiply it by 1,000. In that notation 5,000 is V, and 12,345 is XIICCCXLV (12 thousands, then 345). If you type a number above 3,999, the converter shows this form, but treat it as one convention among several rather than a standard.

Roman numerals chart

Where you still see Roman numerals

They appear on clock faces, in the page numbers of book prefaces, in the names of monarchs and popes (Elizabeth II, Benedict XVI), in film copyright dates, in outlines and legal documents, and in the numbering of sporting events. Reading a film or building date is the most common real-world use, which is why the chart above lists recent years. For other ways of writing numbers, see the number base converter or the multiplication chart, and more tools in the math section.