Roman numbers calculator

Decimal		Roman

Notes:

Practice the roman and decimal numerals

Roman numerals summary

The numeral system which is known as roman numbers was based on the numeral system of the Etruscans who were a sophisticated pre roman civilization located in the center of Italy, the romans used this system to measure lengths and quantities. The roman numerals were used in Europe until the late Middle Ages at around the 14th and 15th centuries.

The roman numbers are presented by 7 Latin letters I, V, X, L, C, D, and M each of them has a different value (see the table bellow). They are arranged so that if a lower value is located at the left of a higher value, then the lower value is reduced from the higher value like IV is equal to

5 − 1 = 4, and if it is located at the right then it is added to the value like

VI is 5 + 1 = 6. Sometime the roman used four consecutives same symbol in order to eliminate the necessity of subtracting values like IIII instead of IV or XXXX instead of XL or CCCC instead of CD.

A clock with roman numerals

Standard numbers values		Extended values
Maximum number up to 4,999		Maximum number up to 4,999,999
Roman	Decimal	Roman	Decimal
I	1
V	5	V v	5000
X	10	X x	10000
L	50	L l	50000
C	100	C c	100000
D	500	D d	500000
M	1000	M m	1000000

Table of roman numbers from decimal:

Size:

roman numbers calculation jscript code

Jscript code to calculate decimal to roman and roman to decimal numbers

// Use this values for the regular roman numbers up to 4,999 //

var decimals = [1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1];

var roman = ["M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V",

"IV", "I"];

// Use this values for the extended roman numbers up to 4,999,999 //

var decimals = [1000000, 900000, 500000, 400000, 100000, 90000, 50000,

40000, 10000, 9000, 5000, 4000, 1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1];

var roman = ["m", "cm", "d", "cd", "c", "xc", "l", "xl", "x", "Mx", "v",

"Mv", "M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I"];

function decimal2Roman(D) {

var R = '';

for (var i = 0; i < decimals.length; i++) {

while (D >= decimals[i]) {

R += roman[i];

D -= decimals[i];

}

return R;

}

function Roman2Decimal(R) {

var D = 0;

for (var i = 0; i <= decimals.length; i++) {

while (R.indexOf(roman[i]) == 0) {

D += decimals[i];

R = R.replace(roman[i], '');

}

return D;

}