1 in Roman numerals

1 = I

Working: I = 1

The number 1 is written as I in Roman numerals.

Roman numerals are built by adding symbol values together from largest to smallest: I = 1. 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, I is 1 symbol long. It is entirely additive: every symbol adds to the running total, with no smaller symbol standing before a larger one. No symbol repeats.

I is the simplest numeral and the origin of the whole system — a single tally mark. It also exposes the system's most significant limitation: there is no symbol for zero, and no way to write one. Roman numerals were a notation for counting things, not a positional number system, which is why arithmetic in them is so unwieldy.

Nearby numbers

Number	Roman numeral
2	II
3	III
4	IV
5	V
6	VI
7	VII
8	VIII
9	IX

Try another value

Decimal number (1–3999)

Roman numeral

MMXXIV

Reference

X10

L50

C100

D500

M1000

Frequently asked questions

How do you write 1 in Roman numerals?

1 is written I. It breaks down as I = 1.

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.