Roman Numerals

Roman numerals are the way the anceint Romans wrote numbers. Instead of digits they use seven letters: I, V, X, L, C, D and M. We still see them today on clock faces, in the names of kings, queens and popes (Elizabeth II, Louis XIV), for the chapters of a book, in film credits and on buildings, where they often show the year the building was finished.

Roman Numerals Converter

Type a number to get its Roman numeral, or type a Roman numeral to find its value. Standard Roman numerals can write every whole number from 1 to 3999.

The Seven Symbols

A sentence to remember the order: “I Value Xylophones Like Cows Do Milk.”

The Rules

1. Add when the symbols go from larger to smaller: VI = 5 + 1 = 6, LXX = 50 + 10 + 10 = 70.
2. Subtract when a smaller symbol stands before a larger one: IV = 5 − 1 = 4, XC = 100 − 10 = 90.
3. I, X, C and M can be repeated up to three times in a row: III = 3, XXX = 30, MMM = 3000. So 4 is IV, not IIII.
4. V, L and D are never repeated and never subtracted: 10 is X, not VV, and 45 is XLV, not VL.
5. There are only six subtractive pairs: IV = 4, IX = 9, XL = 40, XC = 90, CD = 400 and CM = 900. So I is subtracted only from V and X, X only from L and C, and C only from D and M: 99 is XCIX, not IC, and 1999 is MCMXCIX, not MIM.
6. Only one smaller symbol can stand before a larger one: 8 is VIII, not IIX.
7. Apart from the six pairs, the symbols always go from the largest to the smallest.

Because M can be repeated only three times, the largest number we can write this way is 3999 = MMMCMXCIX.

Did you know? Many clock faces show IIII instead of IV. This is an old clockmakers’ tradition, not the standard rule.

How to Write and Read Roman Numerals

To write a number, split it into thousands, hundreds, tens and ones. Write each part with the table below, then put the parts together from left to right. A zero digit is simply skipped.

For example, 2026 = 2000 + 20 + 6. From the table, 2000 = MM, 20 = XX and 6 = VI, so 2026 = MMXXVI. The hundreds digit is 0, so nothing is written for it.

To read a Roman numeral, go from left to right. If a symbol is smaller than the symbol after it, subtract it; otherwise add it. For example,
MCMXCIV = M + CM + XC + IV = 1000 + 900 + 90 + 4 = 1994.

Examples

6 = 5 + 1 = V + I = VI
11 = 10 + 1 = X + I = XI
14 = 10 + 4 = 10 + (5 − 1) = X + IV = XIV
17 = 10 + 7 = X + VII = XVII
35 = 30 + 5 = XXX + V = XXXV
49 = 40 + 9 = XL + IX = XLIX (not IL)
81 = 50 + 30 + 1 = L + XXX + I = LXXXI
400 = 500 − 100 = CD
944 = 900 + 40 + 4 = CM + XL + IV = CMXLIV
1999 = 1000 + 900 + 90 + 9 = M + CM + XC + IX = MCMXCIX (not MIM)
2026 = 2000 + 20 + 6 = MM + XX + VI = MMXXVI
3999 = 3000 + 900 + 90 + 9 = MMM + CM + XC + IX = MMMCMXCIX (the largest)

Roman Numerals from 1 to 100

Numbers Larger than 3999

For larger numbers, a bar is drawn over a numeral. The bar, called a vinculum, multiplies the value by 1000:

V = 5000
X = 10,000
L = 50,000
C = 100,000
D = 500,000
M = 1,000,000

For example, 4000 = IV, 25,000 = XXV and 12,500 = XIID.

Is There a Zero in Roman Numerals?

No, Roman numerals have no zero. The Romans did not need one. In Roman numerals a symbol means the same amount wherever it stands (X is always ten), so there is no empty place to fill. In our number system the place of a digit matters, and zero keeps the places apart: in 205 the 0 shows that there are no tens. In Roman numerals, 205 is simply CCV.

Centuries later, medieval monks who made tables for finding the date of Easter needed to write zero. They used the Latin word nulla (“none”), and later just its first letter, N.

Read more about place value and other ways of writing numbers in Systems of Counting.

Practice

Choose the kind of problems and the range of numbers. You can write numbers in Roman numerals, read Roman numerals, find the numeral that breaks a rule, or read a year as it appears on a building or at the end of a film. Every correct answer earns a point.

See also: Systems of Counting · Roman and Arabic Numerals · Numbers