Roman Numeral Converter

Convert whole numbers into Roman numerals and back again. Enter one value per line to convert a whole list at once — results update instantly and never leave your browser.

Numbers

Roman numerals

Conversions will appear here.

How to use Roman Numeral Converter

1
Choose a direction
Pick Number to Roman to turn whole numbers into Roman numerals, or Roman to Number to read numerals back as digits. The swap button flips the two.
2
Type or paste your values
Enter one value per line. You can convert a single number like 2024 or a whole list at once, and the results update as you type.
3
Read the result
Each line is converted independently. If a value is out of range or not a valid numeral, a clear message explains exactly what to fix.

4
Copy the output
Use the copy button to grab every converted line at once, ready to paste into a document, a spreadsheet, or a design.

Frequently asked questions

How do I convert a number to Roman numerals?

Keep the converter on Number to Roman, type a whole number from 1 to 3999, and the Roman numeral appears instantly. To go the other way, switch to Roman to Number and enter a numeral such as MMXXIV.

What is the largest number in Roman numerals?

Standard Roman numerals run from 1 to 3999, written MMMCMXCIX. There is no symbol for zero and no single letter beyond M, so larger values rely on an overline notation that is rarely used today and sits outside this tool.

How are Roman numerals written?

Seven letters carry the values I is 1, V is 5, X is 10, L is 50, C is 100, D is 500, and M is 1000. A smaller letter before a larger one is subtracted, so IV is 4 and XC is 90, while letters that only descend in value are added together.

Why is my Roman numeral marked invalid?

Roman numerals follow strict rules, so forms like IIII, VV, or IC are not allowed. The converter rebuilds each numeral and rejects anything that is not the standard spelling, which keeps your results accurate.

Can I convert several numbers at once?

Yes. Enter one value per line and every line is converted on its own, so you can turn a long list of numbers or numerals into the other format in a single step.

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