Roman Numerals and Alphabet Converter

Using the Roman numerals and alphabet converter

The calculator will convert positive integer less than 5000 between Roman numerals and alphabet. The largest number you can enter is 4999, or MMMMCMXCIX in Roman numerals format.

About Roman numerals

Roman Numerals are based on seven symbols

• I = 1
• V = 5
• X = 10
• L = 50
• C = 100
• D = 500
• M = 1,000

There are several rules for writing Roman numerals.

• Repeating a numeral up to three times represents addition of the number. For example, XXX represents X + X + X = 30. Only I, X, C, and M can be repeated; V, L, and D cannot be repeated.
• Writing numerals that decrease from left to right represents addition of the numbers. For example, LX represents 50 + 10 = 60 and XVI represents 10 + 5 + 1 = 16.
• TWriting a smaller numeral to the left of a larger numeral represents subtraction. For example, IV represents 5 - 1 = 4 and IX represents 10 - 1 = 9. but the only pairs of numerals that use this subtraction rule are:
  • IV = 5 - 1
  • IX = 10 - 1
  • XL = 50 - 10
  • XC = 100 - 10
  • CD = 500 - 100
  • CM = 1000 - 10

Here is an example about repeating and subtraction rules:
Let's convert a Roman numerals to alphabet number.
MMCMXCIX
= M + M + (M - C) + (C - X) + (X - I)
= 1000 + 1000 + (1000 - 100) + (100 - 10) + (10 - 1)
= 2999

Most used Roman numerals from one to a thousand