What is the largest number in Roman numerals?

The standard system goes up to 3,999 (MMMCMXCIX).

What do the Roman numeral letters stand for?

I=1, V=5, X=10, L=50, C=100, D=500, M=1000.

When a smaller numeral appears before a larger one it is subtracted. I before V means 5 minus 1 equals 4.

roman numeral converter

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Roman numeral reference

I	1	one
IV	4	four (subtractive)
V	5	five
IX	9	nine (subtractive)
X	10	ten
XL	40	forty (subtractive)
L	50	fifty
XC	90	ninety (subtractive)
C	100	one hundred
CD	400	four hundred (subtractive)
D	500	five hundred
CM	900	nine hundred (subtractive)
M	1000	one thousand
MMMCMXCIX	3,999	maximum

How it works

Roman numerals use letters to represent values. When a smaller value appears before a larger one, it is subtracted. Otherwise values are added left to right.

FAQ

What is the largest Roman numeral?

Standard notation goes up to 3,999 — written MMMCMXCIX. Beyond that a vinculum (overbar) is needed.

Is there a Roman numeral for zero?

No — the Romans had no symbol for zero. The concept wasn't part of their mathematics.

Why does IV mean 4?

Subtractive notation: I (1) placed before V (5) means 5 − 1 = 4. The same rule applies to IX, XL, XC, CD and CM.

Is my data stored?

No — all conversion happens in your browser. Nothing is sent to any server.