IX in numbers

IX = 9

Working: IX = 9

The Roman numeral IX represents the number 9.

Reading it left to right, the symbols contribute like this: IX = 9. Roman numerals are read by adding values together, except where a smaller symbol sits immediately before a larger one — that pairing means subtraction, which is why IV is 4 rather than 6.

Structurally, IX is 2 symbols long. It uses the subtractive pair and IX, which must be read as a unit rather than symbol by symbol. No symbol repeats.

IX is one subtracted from ten. It is short specifically to avoid VIIII, which would need five symbols. Roman numerals never repeat a symbol more than three times, and the subtractive pairs exist to enforce that cap.

Related numerals

Roman numeral	Number
IV	4
VI	6
XII	12
XIV	14
XIX	19
XXIV	24
XXIX	29
XXXIX	39

Try another value

Decimal number (1–3999)

Roman numeral

MMXXIV

Reference

X10

L50

C100

D500

M1000

Frequently asked questions

What number is IX in Roman numerals?

IX is 9. The symbols break down as IX = 9.

Why is IV four and not six?

When a smaller symbol comes immediately before a larger one it is subtracted instead of added. I before V means five minus one, giving four. VI, with the I after the V, means five plus one, giving six.

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