How to read Roman numerals

Get to know the seven symbols

Roman numerals are letters used to write numbers. You can spot them on clocks, buildings and film credits. Start with these seven symbols:

When a smaller symbol follows a larger one, add it. In VI, V gives you five and I adds one more. That makes 6.

In VIII, start with five and add three ones. That makes 8.

When a smaller symbol comes first

Some pairs work the other way round: a smaller symbol comes first, and you take it away. In IV, take one away from five. The answer is 4.

These are the usual subtraction pairs:

• IV: one less than five → 4.
• IX: one less than ten → 9.
• XL: ten less than fifty → 40.
• XC: ten less than one hundred → 90.
• CD: one hundred less than five hundred → 400.
• CM: one hundred less than one thousand → 900.

You cannot invent any pair you like. To write 49, use XLIX: XL for forty, then IX for nine. IL is not the usual way to write it.

Older inscriptions sometimes use different forms. Many clocks show four as IIII.

Read a date one piece at a time

Try reading MCMXLIV on a building. Break it into familiar pieces:

• M gives 1,000.
• CM gives 900.
• XL gives 40.
• IV gives 4.

The first two pieces make 1,900. Add forty to reach 1,940, then four more. The year is 1944.

Three more to try

Work out XIV, XLII and XC. Look for subtraction pairs before adding the remaining values.