Roman Numerals — Fun & Easy!

What are Roman Numerals?

Roman numerals are letters used to write numbers.

Roman numerals are a special way of writing numbers using letters instead of normal numbers. They were used a long time ago in ancient Rome. Roman numerals use letters like I, V, X, L, C, D, and M.

Today, we can still see them

• On clock faces (I to XII)
• In book chapters
• In names like King Henry VIII
• Movie sequels or book volumes (e.g., Rocky II)
• To show special events and anniversaries

Roman Letters

These are the 7 basic Roman letters. Learn their values — then you can make numbers up to 4999 without using overlines.

How they combine

• Put letters together from big to small and add (e.g., XV = 10 + 5 = 15).
• Put a smaller before a larger to subtract (e.g., IV = 4).
• Some combos you should remember: IV, IX, XL, XC, CD, CM.

Rules to Write Roman Numerals

These easy rules help you spell Roman numbers correctly.

• Put big first: write largest letters first and add them (e.g., XV = 10 + 5 = 15).
• Use subtraction: put a small letter before a bigger one to subtract (e.g., IV = 4).
• Allowed subtractions: I before V or X; X before L or C; C before D or M.
• Don't repeat more than three times: standard rule, but for thousands many sources accept up to four Ms (e.g., 4000 = MMMM) when you avoid overlines.

Converting Roman Numerals to Numbers

Follow these steps to change a Roman numeral into our normal numbers.

1. Read from left to right.
2. If a letter is followed by a bigger letter, subtract it (e.g., IX → 10 − 1 = 9).
3. Otherwise add the letter values (e.g., XVII = 10 + 5 + 1 + 1 = 17).
4. Check your answer by converting back to Roman — this catches mistakes.

Worked example

XCIX

• XC = 100 − 10 = 90
• IX = 10 − 1 = 9
• Total = 90 + 9 = 99