30 in Roman numerals

XXX

30 = XXX

Working: X = 10, X = 10, X = 10

The number 30 is written as XXX in Roman numerals.

Roman numerals are built by adding symbol values together from largest to smallest: X = 10, X = 10, X = 10. Where a smaller symbol appears before a larger one — as in IV for 4 or IX for 9 — it is subtracted rather than added, which keeps the notation short.

Structurally, XXX is 3 symbols long. It is entirely additive: every symbol adds to the running total, with no smaller symbol standing before a larger one. One symbol repeats three times, which is the maximum the system allows before a subtractive form becomes necessary.

XXX is three tens and the longest permitted run of the X symbol, exactly as III is for I. To write forty the system has to switch to the subtractive XL rather than continue to XXXX, which is the same rule operating one order of magnitude up.

Nearby numbers

Number	Roman numeral
14	XIV
15	XV
16	XVI
18	XVIII
19	XIX
20	XX
25	XXV
40	XL

Try another value

Decimal number (1–3999)

Roman numeral

MMXXIV

Reference

X10

L50

C100

D500

M1000

Frequently asked questions

How do you write 30 in Roman numerals?

30 is written XXX. It breaks down as X = 10, X = 10, X = 10.

What are the seven Roman numeral symbols?

I is 1, V is 5, X is 10, L is 50, C is 100, D is 500, and M is 1,000. All Roman numerals are combinations of these seven symbols, and there is no symbol for zero.

For any other value, use the full Roman Numeral Converter on BrainVert.