Introducing the Roman Numeral Converter — Both Directions with Full Breakdown

The new Roman Numeral Converter is live. Type any integer from 1 to 3999 or any Roman numeral and get the instant conversion — with a full component breakdown showing exactly which symbols compose the result.

What it does

The tool converts in both directions:

• Integer → Roman: 42 → XLII, 2026 → MMXXVI, 3999 → MMMCMXCIX
• Roman → Integer: XIV → 14, MMXXVI → 2026, MMMCMXCIX → 3999
• Auto-detect: type either format and the tool detects which direction to convert

The full breakdown shows each numeral component with its value — XL=40, II=2 for XLII, for example. This makes it useful for learning the subtractive rule (why 4 is IV and not IIII) rather than just getting an answer.

Other features

• Round-trip validation — converts the result back and checks it matches the canonical form, catching non-standard inputs like IIII
• Case-insensitive — xiv and XIV both work, normalised to uppercase
• Example buttons — 1, 4, 9, 42, 2026, 3999, XIV, MMXXVI, and MMMCMXCIX load instantly
• 100% offline — no server, no data transmitted

Where Roman numerals come up

Clock faces, movie copyright years (MMXXVI), Super Bowl numbers, chapter headings, legal document outlines, and music theory chord notation. The learn guide covers the full history, rules, and a quick-reference table.