Roman Numerals to Number

Enter Roman Numerals:

Valid characters: I, V, X, L, C, D, M

Conversion Options

Show ExamplesDisplay common Roman numeral examples

Conversion Result

Common Roman Numerals:

I = 1

IV = 4

V = 5

IX = 9

X = 10

XL = 40

L = 50

XC = 90

C = 100

CD = 400

D = 500

CM = 900

M = 1000

Number Information:

Enter Roman numerals to see information

Note: This tool converts valid Roman numerals to numbers (1-3999).

About This Roman Numerals Converter

This tool converts Roman numerals to Arabic numbers (1-3999). It validates the input according to standard Roman numeral rules and provides detailed information about the converted number.

How to Use This Converter

Step-by-Step Guide:

1. Step 1: Enter valid Roman numerals (I, V, X, L, C, D, M)
2. Step 2: Click "Convert to Number" to see the Arabic number equivalent
3. Step 3: View additional information about the number
4. Step 4: Copy or clear results as needed

Roman Numerals Rules:

• I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1000
• When a smaller numeral appears before a larger one, it's subtracted (IV = 4, IX = 9)
• Otherwise, numerals are added (VI = 6, XI = 11)
• Only I, X, and C can be used for subtraction
• Only one smaller numeral can precede a larger one
• Numerals must decrease from left to right except for subtractive combinations
• Maximum valid Roman numeral is MMMCMXCIX (3999)

Example Conversions:

Input: MCMLXXXVII
Output: 1987

Input: MMXXIII
Output: 2023

Input: MMMCMXCIX
Output: 3999