How to Read Roman Numerals (Chart + Rules)
Learn to read Roman numerals with a simple chart of the seven symbols and the two rules that decode any number.
Learning to read Roman numerals is easier than it looks: once you know seven symbols and two simple rules, you can decode dates on buildings, movie sequels, clock faces and book chapters. Here is everything you need in one short guide.
The seven Roman numeral symbols
Every Roman numeral is built from just seven letters, each with a fixed value:
| Symbol | Value |
|---|---|
| I | 1 |
| V | 5 |
| X | 10 |
| L | 50 |
| C | 100 |
| D | 500 |
| M | 1000 |
Rule 1: add when values fall
When a symbol is followed by one of equal or smaller value, you add them together. So VI is 5 + 1 = 6, and XXVII is 10 + 10 + 5 + 1 + 1 = 27. You simply read left to right and keep a running total.
Rule 2: subtract when a smaller comes first
When a smaller symbol sits before a larger one, you subtract it. IV is 5 − 1 = 4, IX is 10 − 1 = 9, and XL is 50 − 10 = 40.
Quick examples to practise
- XIV = 10 + (5 − 1) = 14.
- XL = 50 − 10 = 40.
- MCMXCIX = 1000 + (1000 − 100) + (100 − 10) + (10 − 1) = 1999.
Let a tool do it for you
Once you understand the rules, you can check any number instantly. Our Roman numeral converter translates both ways between numbers and numerals, and if you are curious about other number systems the number base converter handles binary, hex and more. For the history and full background, Britannica's entry on Roman numerals is a reliable read. Learn the seven symbols once, and the rest is just addition and subtraction.