Roman Numeral Converter

Convert integers (1–3999) to Roman numerals and back. Decode validates canonical form and rejects non-standard spellings. Runs entirely in your browser.

Mode

Input

Output

Standard subtractive notation: I, V, X, L, C, D, M (1, 5, 10, 50, 100, 500, 1000). Valid range 1–3999.