Type a value into either the Arabic-number field or the Roman-numeral field - the other field updates live.
If the value you enter is out of range or the Roman numeral is not in standard form (for example IIII instead of IV), the tool names exactly what is wrong instead of failing silently. Copy the result to your clipboard with one click.
Roman Numeral Converter
Convert a number between Roman numerals and standard Arabic numbers, right in the browser.
Accepts whole numbers from 1 to 3999, the range the standard subtractive Roman notation represents.
Conversion runs locally from a fixed lookup table - nothing is uploaded and no account is required.
Type a value into either the Arabic-number field or the Roman-numeral field and the other field updates live, with no separate Convert button to click.
Use the Copy result button to copy the current value for pasting into a document, spreadsheet, or chat message.
Frequently Asked Questions
What does Roman Numeral Converter do?
Convert a number between Roman numerals and standard Arabic numbers, right in the browser.
What range of numbers does Roman Numeral Converter accept?
Accepts whole numbers from 1 to 3999, the range the standard subtractive Roman notation represents.
Does Roman Numeral Converter handle numbers larger than 3999?
Does not support the vinculum/overline extension for numbers above 3999 - only the standard subtractive notation.