Using the Excel ROMAN Function

Summary
The ROMAN function converts an Arabic number to a Roman numeral as text. If you need to convert Roman numerals to Arabic numbers this is done using the ARABIC function.Syntax
=ROMAN (number, [form])Syntax Breakdown
numberThe number argument is required and is the Arabic number that you would like to convert to a Roman numeral.
form
Form is an optional argument. This is a number used to specify what type of Roman numeral you want. The options for the form argument are as follows:

Usage Notes
The ROMAN function is able to convert an Arabic number into a Roman numeral.Roman Numeral Review
The following chart provides a brief overview of Roman numerals and their Arabic equivalent.

ROMAN Errors
If the number is negative or greater than 3,999, the function returns the #VALUE! error.