Convert numbers to Roman numerals and Roman numerals back to numbers. Supports 1 to 3,999,999 with step-by-step breakdown.
Enter a Number (1 – 3,999,999)
Step-by-Step Breakdown
Free Online Roman Numeral Converter
Our Roman numeral converter instantly translates between Arabic numbers (1, 2, 3) and Roman numerals (I, II, III). Perfect for students, historians, or anyone working with classical numbering systems. Simply enter a number or Roman numeral, and get the conversion with a detailed breakdown of how it's constructed.
Common Use Cases
Academic Writing — Number book prefaces, chapter headings, and outline sections using Roman numerals as required by style guides like MLA and Chicago.
Film & TV Credits — Convert production years to Roman numerals for copyright notices (e.g., MMXXVI for 2026).
Architecture & Monuments — Read cornerstones, building dates, and dedication plaques engraved with Roman numerals.
Clock Faces — Understand the Roman numeral markings on analog clocks and watches (I through XII).
Book Editions — Decode edition numbers on title pages (e.g., Edition XV = 15th edition).
Legal Documents — Interpret ordinal numbering in contracts, amendments, and legislative text.
Quick Reference Examples
IV
4 (Subtractive: 5 − 1)
XLII
42 (XL + II)
XCIX
99 (XC + IX)
CCCLXV
365 (Days in a year)
MCMXCIV
1994 (M + CM + XC + IV)
MMXXVI
2026 (Current year)
How It Works
Converting Numbers to Roman Numerals: The converter breaks down your number into standard Roman numeral values (M=1000, D=500, C=100, L=50, X=10, V=5, I=1) and applies subtractive notation rules (IV=4, IX=9, XL=40, XC=90, CD=400, CM=900).
Converting Roman Numerals to Numbers: The tool parses each Roman symbol, adds values together, and handles subtractive pairs correctly. Invalid Roman numerals will trigger an error message.
Frequently Asked Questions
What numbers can this converter handle?
This converter supports integers from 1 to 3,999,999, which covers standard Roman numeral usage and extended notation with overlines.
How are large Roman numerals written?
Numbers beyond 3,999 use overlines (V̄ = 5,000, X̄ = 10,000) or parentheses to multiply the base value by 1,000. Our converter handles these automatically.
What is subtractive notation?
Subtractive notation places a smaller numeral before a larger one to indicate subtraction (IV = 4, IX = 9). This convention was adopted in medieval times and is now standard.
Why is there no zero in Roman numerals?
The ancient Romans didn't have a concept of zero. The numeral system was additive, not positional, so zero wasn't needed for calculations.
Can I use this for years?
Yes! Simply enter the year (e.g., 2024 → MMXXIV) to see its Roman numeral representation. Great for movie credits, book editions, or events.
Is this converter free to use?
Absolutely. This Roman numeral converter is completely free with no limits or restrictions. Use it as often as you need.