How do I convert a number to a Roman numeral?

Pick 'Number to Roman' in the Mode dropdown, type a whole number from 1 to 3999, and the result appears instantly. For example, 42 becomes XLII and 2026 becomes MMXXVI.

How do I turn a Roman numeral back into a number?

Choose 'Roman to number' in the Mode dropdown and type the numeral, like MMXXVI. The tool reads the standard letters (I, V, X, L, C, D, M) and shows the value, in this case 2026. Letter case does not matter.

What range of numbers does it support?

It handles whole numbers from 1 to 3999, which is the standard range for classic Roman numerals. There is no symbol for zero and no standard way to write numbers above 3999 without overlines, so values outside this range return a friendly error.

Is the converter free and private?

Yes to both. There is no sign-up and no limit, and every conversion runs in your browser using JavaScript, so whatever you type never leaves your device.

Roman Numeral Converter

Input

Mode

Output

What the Roman Numeral Converter does

This tool translates in both directions. It turns an ordinary number into a Roman numeral, so 42 becomes XLII and 2026 becomes MMXXVI, and it reads a Roman numeral back into a plain number. It covers the standard range of 1 to 3999, which is everything classic Roman numerals can express without special overline notation.

It is handy for clock faces, book chapters, movie release years, copyright dates, monument inscriptions, tattoos, and homework. Students, designers, and anyone curious about how a year is written the old way will get an answer in a second.

How to use it

Set the Mode dropdown to either Number to Roman or Roman to number.
Type your value into the text box (a number like 2026, or a numeral like MMXXVI).
Read the converted result instantly as you type, or press Convert.
Copy the output with one click.

That is the whole flow. For Number to Roman, enter a whole number from 1 to 3999. For Roman to number, enter the standard letters in any case.

A quick example

Say you want this year as a numeral. Choose Number to Roman, type 2026, and you get MMXXVI: two thousands (MM), one twenty (XX), and six (VI). Going the other way, MMXXVI reads back to 2026. One common gotcha is invalid input, such as letters that are not Roman digits or a number outside 1 to 3999, which the tool flags rather than guessing.

Everything happens right in your browser, so it is private, free, and needs no sign-up.

Frequently asked questions

How do I convert a number to a Roman numeral?: Pick 'Number to Roman' in the Mode dropdown, type a whole number from 1 to 3999, and the result appears instantly. For example, 42 becomes XLII and 2026 becomes MMXXVI.
How do I turn a Roman numeral back into a number?: Choose 'Roman to number' in the Mode dropdown and type the numeral, like MMXXVI. The tool reads the standard letters (I, V, X, L, C, D, M) and shows the value, in this case 2026. Letter case does not matter.
What range of numbers does it support?: It handles whole numbers from 1 to 3999, which is the standard range for classic Roman numerals. There is no symbol for zero and no standard way to write numbers above 3999 without overlines, so values outside this range return a friendly error.
Is the converter free and private?: Yes to both. There is no sign-up and no limit, and every conversion runs in your browser using JavaScript, so whatever you type never leaves your device.

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Last updated: June 17, 2026