Roman numeral converter
Numbers to Roman numerals and back, from 1 to 3999.
How it’s calculated
Roman numerals are built from I (1), V (5), X (10), L (50), C (100), D (500) and M (1000). A smaller numeral before a larger one is subtracted, so IV is 4 and CM is 900. Only the standard form is accepted, so IIII isn’t treated as 4.