Roman Numeral Converter - atomcalculator.com

Roman Numeral:

Number (1 - 3999):

A Roman Numeral Converter is a tool helps you convert numbers between the Roman numeral system and decimal (Arabic) number system. This converter allows you to enter Roman numerals (eg: MMMDCCXXIV) and quickly find their decimal equivalent.

Roman Numeral Definition

The Roman numeral system originated in ancient Rome and it is widely used throughout Europe until late middle ages. Roman numerals (I, V, X, L, C, D, M) are based on combination of seven letters from the Latin alphabet each representing specific value.

Number	Roman Numeral	Number	Roman Numeral
1	I	4	IV
5	V	9	IX
10	X	40	XL
50	L	90	XC
100	C	400	CD
500	D	900	CM
1,000	M	3,999	MMMCMXCIX

Table 1 displaying unique Roman numerals from 1 to 3,999.

Example 1: MDX to Decimal
M = 1000, D = 500, X = 10
Total = 1000 + 500 + 10 = 1510

Example 2: MMXXIII to Decimal
MM = 2000, XX = 20, III = 3
Total = 2000 + 20 + 3 = 2023

Roman numerals were originally designed to represent numbers from 1 to 3,999 using combination of Latin symbols (I, V, X, L, C, D, M). However, to represent numbers greater than 3,999 is to place a horizontal line (called a vinculum) above a Roman numeral. This horizontal line indicates that the value of the numeral is multiplied by 1000.

Number	Roman Numeral	Number	Roman Numeral
4,000	IV	5,000	V
6,000	VI	7,000	VII
8,000	VIII	9,000	IX
10,000	X	20,000	XX
30,000	XXX	40,000	XL
50,000	L	60,000	LX
70,000	LXX	80,000	LXXX
90,000	XC	100,000	C
500,000	D	1,000,000	M

Table 2 shows Roman numerals beyond 3,999, featuring the vinculum method.

Roman to Decimal conversion

Roman numerals are written and interpreted according to a precise set of rules. These set of rules ensure that numbers are represented consistently and clearly.

Addition Rule: When smaller follows larger roman numerals their values are added. The numerals are arranged in descending order of value from left to right. Each numerals add its value to the whole amount for example: VI = 5 + 1 = 6.

Subtraction Rule: When smaller numerals appear before larger numerals their values are subtracted from the larger numeral. This subtraction rule reduce the length of roman numerals and avoid excessive repetition of numerals for examples: IV = 5 – 1 = 4.

Repetition Rule: A numeral can be repeated up to three times in a row to increase its value. After three times subtraction is used. Also, I , X , C , and M numerals can be repeated. The numerals V , L , and D cannot be repeated for example MMM = 1000 + 1000 + 1000 = 3000

How to use this converter

Step 1: Enter the Roman Numeral you want to convert into the designated input field. For Roman Numerals type the numerals directly (e.g., “MCMXCIV”). Always double check your input and avoid typos.

step 2: Click the calculate button. The calculator will process the input and display the converted result instantly.

1. What are Roman numerals 1 to 1000?

Roman numerals from 1 to 1000: 1 – I, 5 – V, 10 – X, 50 – L, 100 – C, 500 – D, 1000 – M.

2. What is 10000 in Roman numerals?

10,000 is written as X̅ in Roman numerals.

3. What is the meaning of CCCXXXIX?

CCC (300) + XXX (30) + IX (9 (since I before X means 10 – 1 = 9)) = 339