Roman Numeral Converter

Convert integers to Roman numerals and back. Valid range: 1–3999.

Integer

⇄

Roman Numeral

Reference

100

500

1000

About this tool

Convert numbers to Roman numerals and Roman numerals back to decimal numbers - instantly. Supports standard Roman numerals from 1 to 3,999, with a step-by-step breakdown showing which conversion rules were applied. Useful for chapter numbers, clock faces, film copyright dates, Super Bowl naming, and formal outlines.

How to Convert Roman Numerals Online

1Enter a decimal number (1–3999) to convert to Roman numerals.
2Or type a Roman numeral string to convert it to decimal.
3The conversion result appears instantly.
4Review the breakdown showing which numeral rules were applied.

Frequently Asked Questions

What are the Roman numeral values?+

I=1, V=5, X=10, L=50, C=100, D=500, M=1000. Subtractive notation: IV=4, IX=9, XL=40, XC=90, CD=400, CM=900.

What is the largest standard Roman numeral?+

3,999 (MMMCMXCIX). Extensions using vinculum notation reach into the millions, but these are rare outside of historical contexts.

How do I read a Roman numeral?+

Add letters from left to right. If a smaller value appears before a larger one, subtract it: IV = 5 minus 1 = 4, XL = 50 minus 10 = 40.

Why are Roman numerals still used today?+

They appear on clock faces, chapter numbers, film copyright dates (MMXXIV = 2024), Super Bowl numbers, monarchs (Charles III), and formal document outlines.

Looking for a deeper guide on this topic? Browse the Searchlight blog.

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