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Roman Numeral Converter

(fixed for Opera & Chrome)

Enter Number or Numeral to Convert

Number:

Results

Roman Numeral:

Arabic Number:

Instructions

Enter the arabic number or roman numeral that you wish to convert.
Arabic numbers from 1 to 3,999,999 can be converted.
The normal extended notation, meaning times 1000, is to put a bar over the letter.
Because there are no computer letters with bars over them, this form uses lower case letters instead.
1000 is alternatively represented by i (I). This will be converted to m (M).

Please see the Wikipaedia article on Roman Numerals for a more extensive discussion and additional links.

This program uses the algorithm described in detail at MoxLotus.com. However, this program is written in javascript and uses extended numerals increasing the maximum from 3,999 to 3,999,999.

The idea for using i (I) as well as m (M) to represent 1,000 came from ostermiller.org/calc/roman.html though he uses different algorithms. If you are a teacher, though, ostermiller.org/calc/roman.html has the options of both on line and printed tests.

function AtoR(arabic){
    if (arabic > 3999999 || arabic < 1){
        return 'Expect number from 1 to 3,999,999';
    }
    var r_nums = getRnums();
    var a_nums = getAnums();
    var remainder = parseInt(arabic);
    var roman = '', count = 0;

var len=r_nums.length;
    for ( var i=1;  i<len; ++i ){
        while(remainder >= parseInt(a_nums[i]) ){
            if((count++) > 30) return -1;
            roman = roman + r_nums[i];
            remainder = remainder - a_nums[i];
        }
        if(remainder <= 0)break;
    }
    return roman;
}

function RtoA(roman){
    var r_nums = getRnums();
    var a_nums = getAnums();
    var remainder = roman.replace(/i/g, "M");
    var arabic = 0, count = 0, test = remainder;

function getRnums() {
    var r_nums = Array();
    r_nums[1] = 'm';
    r_nums[2] = 'cm';
    r_nums[3] = 'd';
    r_nums[4] = 'cd';
    r_nums[5] = 'c';
    r_nums[6] = 'xc';
    r_nums[7] = 'l';
    r_nums[8] = 'xl';
    r_nums[9] = 'x';
    r_nums[10] = 'Mx';
    r_nums[11] = 'v';
    r_nums[12] = 'Mv';
    r_nums[13] = 'M';
    r_nums[14] = 'CM';
    r_nums[15] = 'D';
    r_nums[16] = 'CD';
    r_nums[17] = 'C';
    r_nums[18] = 'XC';
    r_nums[19] = 'L';
    r_nums[20] = 'XL';
    r_nums[21] = 'X';
    r_nums[22] = 'IX';
    r_nums[23] = 'V';
    r_nums[24] = 'IV';
    r_nums[25] = 'I';
    return r_nums;
}
function getAnums() {
    var a_nums = Array();
    a_nums[1] = 1000000;
    a_nums[2] = 900000;
    a_nums[3] = 500000;
    a_nums[4] = 400000;
    a_nums[5] = 100000;
    a_nums[6] = 90000;
    a_nums[7] = 50000;
    a_nums[8] = 40000;
    a_nums[9] = 10000;
    a_nums[10] = 9000;
    a_nums[11] = 5000;
    a_nums[12] = 4000;
    a_nums[13] = 1000;
    a_nums[14] = 900;
    a_nums[15] = 500;
    a_nums[16] = 400;
    a_nums[17] = 100;
    a_nums[18] = 90;
    a_nums[19] = 50;
    a_nums[20] = 40;
    a_nums[21] = 10;
    a_nums[22] = 9;
    a_nums[23] = 5;
    a_nums[24] = 4;
    a_nums[25] = 1;
    return a_nums;
}
</script>

<table width="100%" class="tableConvert" id="tableConvert">
   <tr valign="top">
    <td>
      <form name="formConvert" id="formConvert" class="formConvert" action='' >
        <fieldset class='spaced'>
          <legend><strong>Enter Number or Numeral to Convert</strong></legend>
          <div class="formLabel">
            <label for="inputNumber">
              Number: 
            </label>
          </div>
          <input  type="text" size="35" maxlength="35"
                  name="inputNumber" id="inputNumber" class="input bold roman"  />
          <br class="clear" />

<fieldset class='spaced'>
          <legend><strong>Results</strong></legend>
          <div class="formLabel">
            <label for="romanNumber">
              Roman Numeral: 
            </label>
          </div>
          <input  type="text" size="35" maxlength="35" readonly="readonly"
                  name="romanNumber" id="romanNumber" class="input bold roman"  />
          <br class="clear" /><br />

<div class="formLabel">
            <label for="arabicNumber">
              Arabic Number: 
            </label>
          </div>
          <input  type="text" size="35" maxlength="35" readonly="readonly"
                  name="arabicNumber" id="arabicNumber" class="input bold roman"  />
          <br class="clear" />
        </fieldset>

<fieldset class='spaced'>
         <legend><strong>Instructions</strong></legend>
        <ul>
          <li>Enter the arabic number or roman numeral that you wish to convert.</li>
          <li>Arabic numbers from 1 to 3,999,999 can be converted.</li>
          <li>The normal extended notation, meaning times 1000, is to put a bar over the letter.</li>
          <li>Because there are no computer letters with bars over them, this form uses lower case letters instead.</li>
          <li>1000 is alternatively represented by <span class='bold'>i (<span class="bar">I</span>)</span>. This will be converted to <span class='bold'>m (<span class="bar">M</span>)</span>.</li>
        </ul>
        </fieldset>
      </form>
    </td>
   </tr>
   </table>

Arabic	Roman	Barred
1	I
5	V
10	X
50	L
100	C
500	D
1,000	M
1,000	i	I
5,000	v	V
10,000	x	X
50,000	l	L
100,000	c	C
500,000	d	D
1,000,000	m	M

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Roman Numeral Converter

Roman Numerals

Arabic

Roman

Barred