Everyday
Percentages, tips & quick math
18 in Roman Numerals
18 in Roman numerals is XVIII. This page shows how 18 is written with the standard subtractive notation (X = 10, VIII = 8), a reference chart, and a converter to try other numbers or decode a numeral back to a number — all computed in your browser. Roman numerals build 18 from the symbols I (1), V (5), X (10), L (50), C (100), D (500) and M (1000), using subtractive pairs like IV (4) and IX (9) rather than repeating four of a symbol.
18 = XVIII
- Breakdown: X = 10, VIII = 8
- Standard subtractive notation (IV not IIII), range 1–3999
Frequently asked questions
How do you write 18 in Roman numerals?
18 is written XVIII — X = 10, VIII = 8. Roman numerals use subtractive pairs (IV = 4, IX = 9, XL = 40, XC = 90, CD = 400, CM = 900) instead of repeating a symbol four times.
What is XVIII in numbers?
XVIII equals 18. To decode, add each symbol's value, subtracting any symbol that appears before a larger one (so IV = 5 − 1 = 4).