Roman Numeral Converter

Convert between Roman numerals and decimal numbers. Enter a Roman numeral (e.g. XIV) or a decimal number (1–3999) and get the conversion with step-by-step breakdown.

Roman

How It Works

Roman numerals use seven symbols to represent numbers. Values are generally written largest to smallest from left to right and added together. When a smaller value appears before a larger one, it is subtracted instead.

Basic Symbols

Symbol	I	V	X	L	C	D	M
Value	1	5	10	50	100	500	1000

Subtractive Notation

Six subtractive combinations are used to avoid four consecutive identical symbols:

IV = 4 (5 − 1)

IX = 9 (10 − 1)

XL = 40 (50 − 10)

XC = 90 (100 − 10)

CD = 400 (500 − 100)

CM = 900 (1000 − 100)

Conversion Rules

Roman to Decimal: Read left to right. If a symbol is smaller than the next one, subtract it; otherwise add it.
Decimal to Roman: Repeatedly subtract the largest possible Roman value, appending its symbol each time.

Reference Chart (1–100)

#	Roman	#	Roman	#	Roman	#	Roman	#	Roman

Notable Roman Numerals

Number	Roman	Context
50	L	Half century, Super Bowl L
100	C	Century, from Latin centum
500	D	From Latin quingenti
1000	M	Millennium, from Latin mille
1776	MDCCLXXVI	US Declaration of Independence
1999	MCMXCIX	End of 20th century
2024	MMXXIV	Current era
3999	MMMCMXCIX	Largest standard Roman numeral

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