🏛️ Roman to Arabic Converter

Convert Roman numerals (I, V, X, L, C, D, M) into their corresponding Arabic decimal numbers with step-by-step breakdown and educational examples.

🏛️ Convert Roman to Arabic

Enter a Roman numeral to convert it to Arabic (decimal) form:

Roman Numeral → Arabic Number
Uses subtractive notation (IV = 4, IX = 9)
Enter uppercase Roman numerals (I, V, X, L, C, D, M)

🏛️ Understanding Roman Numerals

Roman numerals were used by the ancient Romans and are still seen today in clocks, book chapters, movie credits, and formal documents. This converter helps decode these ancient symbols into modern numbers.

📝 Basic Roman Symbols

I = 1

Unus (one)
First letter of "unus"
Can repeat up to 3 times
Base unit

V = 5

Quinque (five)
Half of ten
Cannot repeat
Midpoint marker

X = 10

Decem (ten)
First letter of "decem"
Can repeat up to 3 times
Ten-based system

L = 50

Quinquaginta (fifty)
Middle of century
Cannot repeat
Half-century marker

C = 100

Centum (hundred)
First letter of "centum"
Can repeat up to 3 times
Hundred-based system

D = 500

Quingenti (five hundred)
Middle of millennium
Cannot repeat
Half-millennium marker

M = 1000

Mille (thousand)
First letter of "mille"
Can repeat up to 3 times
Thousand-based system

⚖️ Roman Numeral Rules

➕ Addition Rule

Larger number after smaller
VI = 5 + 1 = 6
XI = 10 + 1 = 11
CL = 100 + 50 = 150
Add values together

➖ Subtraction Rule

Smaller number before larger
IV = 5 - 1 = 4
IX = 10 - 1 = 9
XL = 50 - 10 = 40
Subtract smaller from larger

🔄 Repetition Rule

Can repeat I, X, C, M up to 3 times
III = 3, XXX = 30
CCC = 300, MMM = 3000
V, L, D cannot repeat
Maximum 3 of same symbol

📊 Order Rule

Largest to smallest generally
Exceptions for subtraction
Read left to right
Process each pair carefully

🎯 Common Examples

I
= 1
II
= 2
III
= 3
IV
= 4
V
= 5
VI
= 6
VII
= 7
VIII
= 8
IX
= 9
X
= 10
XI
= 11
XII
= 12
XIII
= 13
XIV
= 14
XV
= 15
XVI
= 16
XVII
= 17
XVIII
= 18
XIX
= 19
XX
= 20
XL
= 40
L
= 50
XC
= 90
C
= 100
CD
= 400
D
= 500
CM
= 900
M
= 1000
MM
= 2000
MMM
= 3000

💡 Roman Numeral Tip: When a smaller number appears before a larger number, subtract the smaller from the larger (IV = 4, IX = 9, XL = 40). This is called subtractive notation and was a Roman innovation.

📜 Historical Context

🏛️ Ancient Rome

Developed around 500 BC
Used for counting and trade
Evolved from Etruscan numerals
Spread with Roman Empire

📚 Modern Usage

Book chapters and volumes
Movie copyright dates
Clock faces and watches
Formal document numbering

🌍 Global Adoption

Used worldwide for centuries
Standardized in Middle Ages
Still taught in schools
Cultural significance

💻 Digital Age

Unicode support for symbols
Used in programming
Web standards and encoding
Typography and design

🧮 Advanced Roman Mathematics

🔢 Large Numbers

Vinculum for multiplication by 1000
MMMM instead of IV̅
Complex notation for millions
Later Roman innovations

➗ Fractions

S (semis) = 1/2
Used for currency and weights
Uncia system (1/12)
Complex fractional notation

📊 Zero Concept

No symbol for zero
Nulla or nihil for nothing
Position-based system lacked zero
Arabic numerals introduced zero

🔄 Conversion Algorithm

Left-to-right processing
Compare adjacent symbols
Add or subtract based on order
Sum all adjusted values

🎭 Famous Roman Numerals

👑 Super Bowl LIV

54th Super Bowl
LIV = 50 + 4 = 54
Common sports notation
American football tradition

⏰ Clock Faces

IIII instead of IV
Traditional watchmaking
Aesthetic preference
Four I's on clock faces

📖 Book Chapters

Chapter I, II, III...
Academic publishing
Legal documents
Formal numbering

🏛️ Architecture

Building dedication dates
MDCCLXXVI = 1776
Historical monuments
Construction milestones