Roman numeral converter and chart

Roman numeral symbols and rules

Roman numerals use seven letters. Read left to right and add the values, except when a smaller symbol comes before a larger one: then you subtract it.

• I, X, C and M repeat at most 3 times in a row: 3 = III, but 4 = IV.
• V, L and D never repeat.
• Only I, X and C can sit before a larger symbol.

How to convert by hand

Break the number into thousands, hundreds, tens and ones, then write each part.

\[ 1989 = 1000 + 900 + 80 + 9 = \text{M} + \text{CM} + \text{LXXX} + \text{IX} = \text{MCMLXXXIX} \]

Roman numerals have no zero and no standard way to write very large numbers, so this tool stops at 3999 (MMMCMXCIX), the largest value under the three-repeat rule.

Where Roman numerals still appear

You see them on clock faces, in movie copyright years, in outlines and book chapters, for kings and popes (Henry VIII), for the Super Bowl (Super Bowl LX in 2026), on cornerstones and for numbering centuries and Olympic Games.

How to use the Roman numeral converter

The Roman numeral converter finds the direction on its own. You do not pick a button.

1. First, type a number from 1 to 3999 to see its Roman form.
2. Next, type a Roman numeral such as XLII to see its value.
3. If a result surprises you, reread the subtraction rule above.
4. Finally, copy the result into your document.

So you switch directions in seconds. The converter updates as you type, which means you see the answer right away.

Quick reference chart for reading Roman numerals

Learn these anchor values and you can read almost any Roman numeral. Combine them to build the rest.

For example, 99 is XCIX, not IC. In fact, only I, X and C can sit before a larger letter, and only before the next two.

Common mistakes with Roman numerals

A few errors come up often, even among adults.

• Writing IIII for 4: some clock faces show it, but the standard rule gives IV.
• Writing VX for 5: V never subtracts. Just write V.
• Writing IC for 99: I only goes before V and X. So write XCIX.
• Repeating V, L or D: VV for 10 is wrong, because X exists.
• Looking for zero: the Romans had none, so the converter does not offer one.

When you doubt a result, split the number. Take thousands, hundreds, tens and ones, write each part, then join them.

Why the converter stops at 3999

With the three-repeat rule, MMMCMXCIX is the largest possible number. To go further, you would need four Ms in a row or a bar over a letter. However, those habits vary by era. So the Roman numeral converter sticks to the classic form, the one you see on clocks, monuments and chapter titles. If you read a larger number, split it into blocks, then add them up. That way you can still check any Roman numeral converter result by hand.

Years and dates in Roman numerals

Roman numerals show up in years, on monuments and in credits. Here are a few examples to check with the converter.

The year 1789 is MDCCLXXXIX, 1998 is MCMXCVIII, 2000 is MM and 2024 is MMXXIV. Also, you read sequels and rulers the same way: Rocky IV, Star Wars Episode IV or Queen Elizabeth II.

To spell a number in words, try Number to words. In addition, the prime factorization calculator helps you play with numbers. Finally, for measurements, open the unit converter. The Roman numeral converter stays the fastest option for years.