Roman ↔ Arabic Converter

Convert between Roman numerals and Arabic numbers. Type in either field — it converts both ways automatically.

Arabic number (1 – 3999)

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Roman numeral

Quick reference

${[['I','1'],['V','5'],['X','10'],['L','50'],['C','100'],['D','500'],['M','1000'],['IV','4'],['IX','9'],['XL','40'],['XC','90'],['CD','400'],['CM','900']].map(([r,a])=>`

${r}${a}

`).join('')}

Batch converter

One number per line, converts all at once