Roman Numeral Converter

The Roman numeral converter converts any Arabic number between 1 and 3999 into its Roman numeral equivalent, or translates a Roman numeral back into a standard Arabic number. Two modes cover the two directions of use: Number mode for individual values and Date mode for converting calendar dates into Roman numeral notation. Auto-detection identifies whether the input is an Arabic number or a Roman numeral, so the direction does not need to be set manually.

• Number mode converts a single value, either an Arabic number such as 2024 or a Roman numeral such as MCMXCIX; auto-detection identifies which one was entered.
• Date mode converts a full calendar date, accepted as MM/DD/YYYY, YYYY-MM-DD, or a standalone four-digit year; month, day, and year each convert independently into Roman numerals.
• A step-by-step breakdown option shows how an Arabic number decomposes into its Roman numeral components. For example, 1994 breaks down as 1000 (M) + 900 (CM) + 90 (XC) + 4 (IV) = MCMXCIV.
• Roman numeral conversion follows standard subtractive notation rules. The values I (1), V (5), X (10), L (50), C (100), D (500), and M (1000) combine with subtractive pairs IV (4), IX (9), XL (40), XC (90), CD (400), and CM (900).
• An uppercase or lowercase output setting switches between uppercase (XIV) and lowercase (xiv) forms.
• Inputs and settings persist automatically between visits, so returning to the page restores the previous session.

Converting 2024 follows the same decomposition as any other year: 2000 (MM) + 20 (XX) + 4 (IV) = MMXXIV. Reversing the process, MMXXIV parses back into MM (2000), XX (20), and IV (4) to recover 2024.

Roman numerals appear across many disciplines and everyday contexts. Converting between numeral systems helps with reading historical documents, formatting creative works, and verifying inscriptions on buildings or monuments.

• Education: Homework answers can be verified by checking the breakdown of any number from 1 to 3999, showing how subtractive notation works with pairs like IV and CM.
• History and Architecture: Dates inscribed on buildings, monuments, and cornerstones decode directly: the numeral MDCCLXXVI reads as 1776.
• Publishing and Media: Chapter numbers, volume numbers, and sequel titles use Roman numerals: 14 converts to XIV for a chapter heading, and a film sequel numbered VII corresponds to the seventh installment.
• Legal Documents: Outline numbering in contracts and briefs follows Roman numeral hierarchies; converting the numeral from a section header confirms its ordinal position.
• Event Planning: Anniversary years, Super Bowl numbers, and Olympic numbering commonly appear in Roman numerals: 58 converts to LVIII for a Super Bowl graphic, and 25 converts to XXV for a silver anniversary invitation.
• Clock and Watch Design: Clock faces using Roman numerals traditionally show IIII rather than IV at the four position, while IX remains standard for nine; numeral placement can be checked against that convention.
• Genealogy: Dates on old family records, gravestones, and church registers written in Roman numerals decode component by component, with month, day, and year converting independently for verification.