Why are some numerals subtractive, like IV for 4?

Roman numerals use subtractive notation for four specific cases (IV=4, IX=9, XL=40, XC=90, CD=400, CM=900) to avoid writing a symbol four times in a row; the calculator's greedy algorithm applies these pairs automatically.

Why is there an upper limit of 3999?

Standard Roman numerals have no symbol for 5,000 or higher without adding overline notation, so conversions are limited to the conventional 1-3999 range.

Roman Numeral Converter

Convert between numbers and Roman numerals.

How this is calculated

Greedy subtraction of the largest matching Roman numeral value/symbol pairs

Assumptions used in this calculation

Range: Standard Roman numerals only support values 1-3999.

About this calculator

Converts numbers (1-3999) to Roman numerals and Roman numerals back to numbers, in both directions.

Worked example

1994

Result: MCMXCIV

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Frequently asked questions

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Convert numbers between binary, octal, decimal and hexadecimal.

Roman Numeral Converter

About this calculator

Frequently asked questions

Why are some numerals subtractive, like IV for 4?

Why is there an upper limit of 3999?

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