Everyday utility

Roman Numeral Converter

Convert any integer from 1 to 3999 to Roman numerals, or decode Roman numerals back to integers. Use this Data and utilities tool to enter your numbers, review the result, and understand the key assumptions before making the next decision.

What you get
A focused calculator, clear explanation, common questions, and useful next tools.
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Result
Explanation
Common questions
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How this calculator works
The result depends on the numbers you enter and the assumptions shown below.

Roman numerals use I(1), V(5), X(10), L(50), C(100), D(500), M(1000). Subtractive notation is used for 4, 9, 40, 90, 400, 900 (e.g., IV=4, IX=9, XL=40, XC=90, CD=400, CM=900).

Review the inputs carefully and treat the output as an estimate. For decisions involving money, taxes, health, law, or security, compare the result with trusted professional guidance when needed.

Frequently asked questions

What is the largest Roman numeral?

Standard Roman numerals go up to MMMCMXCIX (3,999). Larger numbers traditionally used a bar over the numeral to multiply by 1000.