Convert numbers and Roman numerals both ways. This free Roman numeral converter handles 1 to 3999, validates the numeral so only correct forms are accepted, and shows the expanded value of each symbol.
Convert
Standard Roman numerals run from 1 (I) to 3999 (MMMCMXCIX). Enter a number to get its Roman form, or a Roman numeral to read it as a number.
Roman numeral
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Enter a value
Expanded
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The seven symbols are I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1000. A smaller symbol before a larger one means subtraction (IV = 4, IX = 9, XL = 40, CM = 900).
Use this free Roman numeral converter to translate numbers into Roman numerals and back. Enter a number from 1 to 3999, or type a Roman numeral to read it as a number.
What this Roman numeral converter does
A Roman numeral converter changes a number into Roman numerals (and the reverse). It validates the numeral so only correctly-formed standard numerals are accepted, and shows the expanded breakdown.
Roman numeral symbols
Symbol
Value
I
1
V
5
X
10
L
50
C
100
D
500
M
1000
How Roman numerals work
Add symbols from largest to smallest: XVII = 10 + 5 + 1 + 1 = 17
A smaller symbol before a larger one subtracts:
IV = 4, IX = 9, XL = 40, XC = 90, CD = 400, CM = 900
So 2024 = MMXXIV and 1994 = MCMXCIV.
Rules and limits
Standard Roman numerals run from 1 to 3999 (there’s no zero). A symbol like I, X, C or M repeats at most three times in a row, and only one subtractive pair is used at a time — which is why 4 is IV, not IIII. The converter rejects invalid forms.
How to use the Roman numeral converter
Choose number → Roman or Roman → number.
Type your number or numeral.
Read the conversion and the expanded breakdown.
Roman Numeral FAQ
How do I convert a number to Roman numerals?
Enter the number (1–3999) and the converter builds the numeral from largest to smallest symbols — for example, 2024 becomes MMXXIV.
How do I read a Roman numeral as a number?
Switch to "Roman → number" and type the numeral. The converter adds the symbols, applying subtraction where a smaller one precedes a larger one — so MCMXCIV is 1994.
Why is 4 written IV and not IIII?
Standard rules use subtraction: a symbol can't repeat four times, so 4 is "one before five" (IV) and 9 is IX.
What is the largest Roman numeral?
In the standard system it's 3999, written MMMCMXCIX. There's no symbol for zero or for numbers above 3999 without extensions.
What do the letters mean?
I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1000. Other values combine these symbols.
Is the Roman numeral converter free?
Yes, this Roman numeral converter is completely free, needs no sign-up, and gives instant results in your browser.
