Roman Numeral Converter:

A letter with a bar over it multiplies that value by 1,000. For example, M equals 1,000,000. These numbers can be entered by putting an underscore before the letter, for example, _M will mean M.
Technically, 4 million or above cannot be represented in roman numerals, however I have added functionality for it.

Integer: ConvertReset ​ Copy w/ macronsCopy w/ underscores
Roman Numeral: ConvertReset Copy

All Roman Numerals:

Roman Numeral	Value
I	1
V	5
X	10
L	50
C	100
D	500
M	1,000
I ( _I )	1,000
V ( _V )	5,000
X ( _X )	10,000
L ( _L )	50,000
C ( _C )	100,000
D ( _D )	500,000
M ( _M )	1,000,000