Here you will find all the information about the Roman Numerals. In addition to the calculator for converting Roman numerals, you will find below all the rules for Roman numerals as they are taught in mathematics lessons today, as well as other historical rules and descriptions. Examples for converting Roman numerals round off the topic.
Contents on the topic 'Roman Numerals'
- Introduction to Roman Numerals
- Input 'Help' on the Calculator
- Rules for Roman Numerals
- Historical Deviations from Rules
- Example: Convert Decimal Number to Roman Numeral
- Example: Convert Roman Numeral to Decimal Number
- Questions and Answers
Roman or decimal number
Please enter either a decimal number or a Roman numeral, i.e., a character string consisting of the upper- or lower-case letters M, D, C, L, X, V or I. The calculator automatically recognises which number format you have entered and converts a decimal number into a Roman numeral accordingly or, conversely, converts a Roman numeral into a decimal number.
With the subtraction rule, two preceding characters are allowed for subtraction instead of just one.
Example: Not only IX = 9, but also IIX = 8 is allowed. According to the school rules, IIX would not be allowed, but VIII should be used instead.
I and X may not precede only one of the next two larger symbols, but each larger symbol..
Example: Not only IV = 4 and IX = 9, but also IC = 99 is allowed. According to the school rules, IC would not be allowed. XCIX should be used instead.
A combination of deviation 1 and deviation 2 is also encountered. Thus, two characters for subtraction may be preceded by a symbol other than the next two largest.
Example: IIC = 98. Based on the school rules, IIC would not be allowed. XCVIII should be used instead.
More online calculators
As source for the information in the 'Roman Numerals' category, we have used in particular:
This page of the 'Roman Numerals' category was last edited or reviewed by Michael Mühl on February 20, 2023. It corresponds to the current status.
Changes in this category "Roman Numerals"
- Publication of the topic Roman Numerals together with the corresponding texts.
- Editorial revision of this page