Roman Numeral Calculator
Roman Numeral Converter
Convert between Arabic numbers and Roman numerals with ease.
Number to Roman Numeral
Convert Arabic numbers to Roman numerals using additive and subtractive principles
MMXXIV
Roman numeral
Understanding Roman Numerals
Roman numerals are a numeral system that originated in ancient Rome and remained the usual way of writing numbers throughout Europe well into the Late Middle Ages. Numbers in this system are represented by combinations of letters from the Latin alphabet.
Basic Symbols and Values
I
1
V
5
X
10
L
50
C
100
D
500
M
1000
Rules of Roman Numerals
- Addition Rule: When a smaller numeral is after a larger numeral, add them (e.g., VI = 5 + 1 = 6)
- Subtraction Rule: When a smaller numeral is before a larger numeral, subtract it (e.g., IV = 5 - 1 = 4)
- Repetition Rule: No more than three identical numerals in a row (e.g., III = 3, but 4 is IV not IIII)
- Order of Magnitude: Only I, X, and C can be used for subtraction, and only before the next two higher numerals
Common Examples
IV
4
IX
9
XL
40
XC
90
CD
400
CM
900
Modern Usage
While Roman numerals are no longer used for everyday arithmetic, they still appear in various contexts today: clock faces, book chapters and volumes, movie sequels, sporting events (like Super Bowl LVII), monarch names (King Charles III), and building cornerstones.
Frequently Asked Questions
What are the basic Roman numeral symbols?
The basic Roman numeral symbols are: I (1), V (5), X (10), L (50), C (100), D (500), and M (1000).
How does the subtraction principle work in Roman numerals?
When a smaller numeral appears before a larger numeral, it is subtracted. For example, IV means 4 (5-1), IX means 9 (10-1), and XL means 40 (50-10). This only applies to specific pairs: I before V or X, X before L or C, and C before D or M.
What is the largest number that can be represented in Roman numerals?
There's no theoretical maximum, but practical usage typically goes up to 3,999 (MMMCMXCIX). For larger numbers, a bar is placed over the numeral to multiply it by 1,000, but this is rarely used in modern contexts.
Why are there no zeros in Roman numerals?
The Roman numeral system was developed before the concept of zero as a number was established. It's a additive/subtractive system rather than a place-value system like our modern Arabic numerals.
Can the same symbol be repeated more than three times?
No, Roman numerals follow the 'three-in-a-row' rule. You cannot have more than three of the same symbol in sequence. That's why 4 is written as IV instead of IIII, and 40 is XL instead of XXXX.