This calculator provides a means to translate a roman numeral into a standard Arabic integer; ie., translate MMXIV into 2014. 

The calculator contains a button for each of the Roman Numeral constants: I, V, X, L, C, D, M.  Clicking any one of these buttons displays the Arabic integer value for the Roman Numeral equivalent. 

You can use the Add and Subtract buttons to manually combine the Roman Numeral constants.  See the Notes Page for an explanation of how to use he constants with these addition and subtraction buttons.

The Translate button provides the means to enter a large Roman Numeral, following the rules for ordering the digits of the Roman Numeral, and see the resultant Arabic integer value.  This button uses the equation: Translate Roman Numeral.  So, if you use this button and enter DLIX into the equation accessed with the Convert button, the displayed result will be 556.

Notes

 Basic Roman Numerals ===

A number is represented in Roman Numeral notation as a combination of letters, generally capitalized.  The letter used, in order of magnitude are I, V, X, L, C D M, representing respectively: 1, 5, 10, 50, 100, 500, 1000.  The Roman Numerals are written with the letters representing largest values on the left and decreasing in values to the right.  As a simple example the number 155 would be written CLV.

There is no zero in the Roman Numeral system.

A small set of additional rules are used to avoid repeating the letters more than three times.  So, for example, any instance of 4 or 9 is written with a subtracted value preceding a larger value.  Here are key examples of the subtraction notation for Roman Numerals:

• The number 4 is written as IV (not as IIII).
• The number 9 is written as IX (not as VIIII). 
• The number 40 is written as XL (not as XXXX).
• The number 90 is written as XC (not as LXXXX)
• The number 400 is written as CD (not as CCCC)
• The number 900 is written as CM (not as DCCCC)

The integer number through 25 in Roman Numerals are as follows:

The Calculator Tabs

The Calculator has two tabs and each tab has multiple buttons for either equations or constants that help you represent Roman Numerals in Arabic form.

Roman to Arabic tab

On the Roman to Arabic tabs are buttons for each of the Roman numeral constants: I, V, X, L, C, D, N.  Clicking any one of these buttons displays the Arabic integer value for the Roman Numeral Equivalent.  These constants can be added and subtracted but remember that to ensure correct Roman Numeral representation, the order is from highest value letter to lowest value letter respecting the subtraction logic rules.

The Convert button provides the means to enter a large Roman Numeral, following the rules for ordering the digits of the Roman Numeral, and see the resultant Arabic integer value.  So, if you enter DLIX, for example, into the Convert equation's input fields in order, the vCalc result will be 556.

Value of Roman Numerals

On the Value of Roman Numerals tab is the basic capability to do Roman Numeral number construction -- if you follow the digit ordering rules and the subtraction rules for constructing Roman Numerals.  The equations on the Value of Roman Numerals tab can be added and or subtracted together.  If you add several Roman Numeral letters as follows, you will be presented an Arabic result.  Here's how:

Click the L button

History of Roman Numerals

Roman Numerals are an archaic numbering system seldom used in today's world.  Roman Numerals are the basis for the numeric system used by ancient Romans. Latin letters were used in sequence to represent numeric values.

Roman Numerals were replaced by the Arabic numerals that are used today.  Roman Numerals are still used in some instances to represent things like calendar years and most often used as more of an artistic adornment.  For example, in the credits of movies you will sometimes see the year the movie was released represented in Roman Numerals.