Convert between decimal numbers and Roman numerals with step-by-step breakdown
This Roman numeral converter supports two conversion modes: decimal (Arabic) numbers to Roman numerals and Roman numerals back to decimal. It handles values from 1 to 3,999 — the classic range of Roman numeral representation. The decimal-to-Roman mode provides a step-by-step breakdown showing how each place value is converted.
Traditional Roman numerals do not have standardized symbols for values beyond 3,999 (MMMCMXCIX). While later conventions introduced a vinculum (bar) to multiply by 1,000, the classical system — and this converter — focuses on the 1–3,999 range for clarity and historical accuracy.
Subtractive notation places a smaller numeral before a larger one to indicate subtraction. For example, IV means 5 − 1 = 4, and XC means 100 − 10 = 90. This avoids writing four identical symbols in a row (e.g., IIII becomes IV). The standard subtractive pairs are IV, IX, XL, XC, CD, and CM.