How to Convert Roman Numerals

Roman numerals is a system of numbers which uses the letters of the alphabet.[1] It is still occasionally used today, especially when representing years.

Steps

  1. Image titled Convert Roman Numerals Step 1
    1
    Know which letters stand for which numbers.
    • I is 1, V is 5.
    • X is 10, L is 50.
    • C is 100, D is 500.
    • M is 1000.
  2. Image titled Convert Roman Numerals Step 2
    2
    Locate the largest symbol within the number. This should be either the first or the second symbol.
  3. Image titled Convert Roman Numerals Step 3
    3
    If the largest symbol appears first, count how many times it appears in an uninterrupted row. This should be between one and three times. Multiply its value by the number of appearances and add this amount to the total.
  4. Image titled Convert Roman Numerals Step 4
    4
    If the largest symbol appears second, subtract the value of the symbol before it from its value. Add this amount to the total.
  5. Image titled Convert Roman Numerals Step 5
    5
    Repeat steps 2-4 with the numbers you have not yet accounted for.
  6. Image titled Convert Roman Numerals Step 6
    6
    Add up the values of each set of numbers to find the total value of the entire numeral.

Tips

  • In modern Roman numerals, the following rules apply:
    • Only I, X, C and M may be repeated, and each no more than three times in sequence.
    • A large symbol can only require one smaller symbol to be subtracted from it at a time.
    • Only I, X and C may be subtracted, and each only from values up to and including the next highest of the repeatable symbols.
  • Older styles of writing Roman numerals may break the above rules.

Article Info

Categories: Mathematics | Conversion Aids