The Guide to Roman Numerals

Roman numerals originated in ancient Rome and remained the common way of writing numbers throughout Europe well into the Middle Ages. They are a fascinating system based on combinations of letters from the Latin alphabet. Understanding how to read and write them is a great skill for appreciating history, from ancient texts to the dates on old buildings.

How to Read and Write Roman Numerals

The system is based on seven key symbols:

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

These symbols are combined using two simple rules:

1. The Additive Rule: When a symbol of equal or lesser value is placed after a symbol of greater value, the values are added. For example, VI is 5 + 1 = 6, and LXX is 50 + 10 + 10 = 70.
2. The Subtractive Rule: This is the clever part. When a symbol of lesser value is placed *before* a symbol of greater value, the lesser value is subtracted from the greater. For example, IV is 5 - 1 = 4, and XC is 100 - 10 = 90. This rule prevents needing four identical characters in a row (like IIII).

Where Are Roman Numerals Used Today?

While Arabic numerals (0, 1, 2, 3...) have replaced them for mathematics, Roman numerals still appear in many places:

• On the faces of clocks and watches.
• For the Super Bowl number (e.g., Super Bowl LVIII).
• In the credits of movies and TV shows to denote the year of production. For date-related math, see our Date Calculator.
• In the names of monarchs and popes (e.g., Queen Elizabeth II, Pope John Paul II).
• For numbering book chapters, outlines, and recurring events like the Olympic Games. You can find your birth year in Roman numerals with our Age Calculator!