🔢 Number Tools

Roman Numeral Converter

Convert numbers to Roman numerals or Roman numerals to numbers. Supports 1 to 3999. Shows a full symbol breakdown.

Roman Numerals
Roman numeral symbols
${[['I',1],['V',5],['X',10],['L',50],['C',100],['D',500],['M',1000]].map(([s,v])=>`
${s}
${v}
`).join('')}

How to use the Roman Numerals

1

Convert numbers to Roman numerals

Enter any whole number from 1 to 3999. The Roman numeral appears instantly with a full breakdown showing how each part contributes to the total. Roman numerals cannot represent 0 or negative numbers, and 3999 (MMMCMXCIX) is the traditional maximum using standard notation.

2

Read Roman numerals

Switch to "Roman → Number" and type any Roman numeral string. The tool validates the input and converts it to a number, explaining any subtractive notation (e.g. IV = 4, IX = 9, XC = 90). Invalid Roman numerals show an error with an explanation of what went wrong.