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Roman Numeral Converter

Convert numbers to Roman numerals and back, both directions, live, on your device. Handles 1 to 3,999,999.

Number → Roman numerals Enter a whole number from 1 to 3,999,999.

Result appears here

Roman numerals → Number Letters I V X L C D M. Use an overline value? Wrap thousands like (V) for 5,000.

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The seven symbols

100

500

1,000

Subtractive pairs (IV = 4, IX = 9, XL = 40, XC = 90, CD = 400, CM = 900) keep numerals short. Standard numerals only reach 3,999 (MMMCMXCIX). For larger values, Roman scribes drew an overline (vinculum) over a numeral to multiply it by 1,000: an overlined V is 5,000 and an overlined X is 10,000. This tool shows the overline above, and accepts (V) parenthesis notation when you type, since overlines are hard to enter on a keyboard.

About Roman Numeral Converter

Roman Numeral Converter is a free, private tool that runs entirely in your web browser. Type any whole number from 1 to 3,999,999 and get its Roman numeral instantly, or paste a Roman numeral and get the number back. Everything happens on your device: nothing is uploaded to a server, no sign-up is required, and the tool keeps working offline. It supports the full vinculum (overline) notation for values above 3,999, and accepts parenthesis input like (V) for 5,000. Like every free online tool by Digital Heroes, it is completely free with no limits.

What you can do

Convert any number to Roman numerals instantly: type a whole number and see the result live.

Decode Roman numerals back to a number: paste any Roman numeral and get the integer value.

Work with large numbers up to 3,999,999 using overline (vinculum) notation, shown visually above the numeral.

Enter overline values with parentheses: type (V) for 5,000 or (X)CMXCIX for 10,999 without needing special characters.

Copy either result to your clipboard with one click.

Use the symbol reference to look up all seven Roman numeral letters and their values.

How to use Roman Numeral Converter

Open Roman Numeral Converter in your browser. No signup, no install required.

To convert a number to Roman numerals: type a whole number (1 to 3,999,999) into the top field. The result appears instantly below it.

To convert Roman numerals to a number: type or paste the Roman numeral (for example, MMXXVI) into the bottom field. The number appears below it.

For values above 3,999, use parenthesis notation for the overline group, such as (V)CMXCIX for 5,999.

Click Copy next to either result to copy it to your clipboard.

Frequently asked questions

Is Roman Numeral Converter free?

Yes. Roman Numeral Converter is completely free for everyone. No sign-up, no account, and no usage limits.

Is it private? Are my files uploaded anywhere?

No. Roman Numeral Converter runs entirely in your browser on your own device, so your data never leaves your computer and nothing is uploaded to a server.

Does it work offline?

Yes. This tool is a Progressive Web App. Once the page has loaded it keeps working offline, and you can install it as an app from your browser.

Do I need to install anything or create an account?

No. Just open the page and start using it. Installing it as an app is optional and only adds offline convenience.

What does Roman Numeral Converter do?

Roman Numeral Converter converts whole numbers (1 to 3,999,999) to Roman numerals and converts Roman numerals back to numbers. It supports overline notation for values above 3,999 and accepts parenthesis input for large values.