Roman Numerals: Complete Chart and How to Read Them

Roman numerals are all around us — on clock faces, in movie credits, on monuments, in book chapters, and after the names of kings and popes. Yet most people can read I, V, and X and then get lost. This guide gives you the complete system: the chart, the rules, and the logic that makes any Roman numeral readable.

The seven symbols

The entire system is built from just seven letters:

I = 1        C = 100
V = 5        D = 500
X = 10       M = 1000
L = 50

Every Roman numeral, no matter how large, is a combination of these seven symbols. Memorize them and you are most of the way there.

The two rules

Reading Roman numerals comes down to two simple rules about order:

• Addition: when a symbol is followed by one of equal or smaller value, you add. So VI is 5 + 1 = 6, and XII is 10 + 1 + 1 = 12.
• Subtraction: when a smaller symbol comes before a larger one, you subtract it. So IV is 5 − 1 = 4, and IX is 10 − 1 = 9.

The subtraction rule exists to avoid writing four identical symbols in a row. Instead of IIII for 4, you write IV.

The subtractive pairs

Only six specific subtractive combinations are valid — worth memorizing as a set:

IV = 4       XL = 40      CD = 400
IX = 9       XC = 90      CM = 900

Notice the pattern: you only ever subtract powers of ten (I, X, C) and only from the next one or two steps up.

Reading a big number

Work left to right, largest to smallest. Take MCMXCIV (the year 1994):

M   = 1000
CM  = 900
XC  = 90
IV  = 4
-----------
      1994

Break it into chunks — thousands, hundreds, tens, ones — and each chunk is easy.

Why there is no zero

Roman numerals have no symbol for zero, because the system predates the concept of zero as a number in European mathematics. The Romans counted on boards where an empty column simply stayed empty — they never needed a placeholder digit. Zero arrived in Europe much later, via Indian and Arabic mathematics.

The IIII on clocks

If you look closely at many traditional clock faces, the 4 is written IIII rather than the "correct" IV. This is a deliberate horological tradition, partly for visual balance with the VIII opposite it on the dial. Outside of clockmaking, IV is the standard form.

The practical limit

Standard Roman numerals go up to 3999 (MMMCMXCIX). Larger numbers required an overline to multiply a symbol by 1000, but that notation is rare and inconsistent, so converters conventionally stop at 3999.

To convert any number to a Roman numeral or decode one instantly — with validation that catches malformed numerals — use the converter below.