Tuesday, August 4, 2015

RNC: Roman Numeral Converter

Update Sep 4, 2015


How to Use

Type or paste the number on the input. It can be Roman numeral or standard numeral. You'll see the output.
This works for positive integer input.

About Zero, Negative Number, and Fractions

About Zero
There's no zero (0) number in Roman numerals system.
But there's that word nulla.
RNC will return the initial of the word, which is N, if you put 0 on the input box.
BUT, because N isn't actually a Roman numeral, hence if you type N on the input box, it will return error.
This works only from standard numeral to Roman numeral conversion.
About Negative Number
They haven't discovered the "concept" of negative number in that era.
In another words, there's no negative number for Roman numerals system.
About Fractions
There are fractions in Roman Numeral.
But because nowadays we never (like, ever) use it (Roman numeral fractions), RNC isn't included with it.

The Sequence

The system consists of these letters: I, V, X, L, C, D, and M.

  • I: 1
  • V: 5
  • X: 10
  • L: 50
  • C: 100
  • D: 500
  • M: 1000


  • I: 1
  • II: 2
  • III: 3
  • IV: 4
  • V: 5
  • VI: 6
  • VII: 7
  • VIII: 8
  • IX: 9
  • X: 10
  • XI: 11
  • XXII: 22
  • XXXV: 35
  • XLIV: 44
  • LIII: 53
  • CD: 400
  • CDL: 450
  • ML: 1050
  • and so on...

The smaller digit is used as subtractor of the larger one.
It is placed in front (the left side) of the larger digit.

The smaller or equal digit is used as adder.
It is placed behind (on the right side) the digit we wanna add.

I suppose you can observe the addition/subtraction rules from the list above and try it on the tool.

Also, the largest digit is 1,000 (M) - one thousand. Because, you know, it was the ancient time. Therefore, like, the number 10,000,000, will be converted to Roman numerals as 10,000 letters of M.


For neat idea structure (in JavaScript):