Roman Numerals Converter

How to Convert Roman Numerals?

Roman numerals are a numeral system that originated in ancient Rome. To convert between Roman numerals and decimal numbers:

1. Decimal to Roman: Break down the number into thousands, hundreds, tens, and ones. Convert each part using the Roman numeral symbols (I, V, X, L, C, D, M).
2. Roman to Decimal: Read the Roman numeral from left to right. Add the values of symbols, but if a smaller symbol appears before a larger one, subtract the smaller value instead.

Roman Numeral System Principles

1. Basic Symbols

Roman numerals use seven basic symbols: I (1), V (5), X (10), L (50), C (100), D (500), and M (1000). These symbols are combined to represent any number.

2. Additive Notation

When symbols are arranged from largest to smallest (left to right), their values are added. For example: VI = 5 + 1 = 6, and LX = 50 + 10 = 60.

3. Subtractive Notation

When a smaller symbol appears before a larger one, subtract the smaller value. Only I, X, and C can be subtracted. Examples: IV = 5 - 1 = 4, IX = 10 - 1 = 9, XL = 50 - 10 = 40, XC = 100 - 10 = 90, CD = 500 - 100 = 400, CM = 1000 - 100 = 900.

4. Repetition Rules

• I, X, C, and M can be repeated up to three times consecutively
• V, L, and D cannot be repeated
• Repetition means addition: III = 3, XXX = 30, CCC = 300

5. Subtraction Rules

• Only I, X, and C can be used as subtractive numerals
• I can be subtracted from V and X only
• X can be subtracted from L and C only
• C can be subtracted from D and M only
• Only one smaller symbol can appear before a larger symbol

6. Limitations

Traditional Roman numerals can represent numbers from 1 to 3999. There is no symbol for zero. Numbers beyond 3999 require special notations (like a bar over numerals for multiplication by 1000).

Roman Numeral Symbols

I = 1

V = 5

X = 10

L = 50

C = 100

D = 500

M = 1000

Conversion Examples

1 = I

4 = IV

9 = IX

27 = XXVII

49 = XLIX

99 = XCIX

400 = CD

500 = D

900 = CM

1984 = MCMLXXXIV

2024 = MMXXIV

3999 = MMMCMXCIX