Roman Numeral Converter – Convert Numbers to Roman Numerals
Convert between Arabic numbers and Roman numerals online instantly. Bidirectional conversion supporting 1–3999 with full breakdown—free, fast, and browser-based.
Runs in your browser
WebAssembly, no server
No signup required
Open and use instantly
Files stay private
Nothing leaves your device
How It Works
Select conversion direction: Number to Roman, or Roman to Number
Type your number or Roman numeral in the input field
The result appears instantly
Key Features
- Arabic number to Roman numeral conversion (1–3999)
- Roman numeral to Arabic number decoding
- Bidirectional — toggle between conversion modes
- Real-time conversion as you type
- Validates Roman numeral input
- Shows conversion breakdown/explanation
- Copy result to clipboard
- No sign-up required
- 100% browser-based
- Free with no limits
- Mobile-friendly
About This Tool
Our Roman Numeral Converter lets you convert any number between 1 and 3999 to Roman numerals and decode any Roman numeral string back to its decimal value — instantly.
Roman Numeral Quick Reference
| Symbol | Value |
|--------|-------|
| I | 1 |
| V | 5 |
| X | 10 |
| L | 50 |
| C | 100 |
| D | 500 |
| M | 1000 |
Subtractive Notation
Roman numerals use subtractive notation for certain values — IV = 4, IX = 9, XL = 40, XC = 90, CD = 400, CM = 900.
Common Uses
- Understanding copyright years (MMXXVI = 2026)
- Movie sequel numbering (Super Bowl LX)
- Clock faces and book chapter numbering
- Historical dates in academic writing
- Architectural inscriptions
Bidirectional Conversion
Convert Arabic to Roman (123 → CXXIII) or Roman to Arabic (CXXIII → 123) with a single toggle.
Frequently Asked Questions
Standard Roman numerals support 1 to 3,999 (MMMCMXCIX). Numbers beyond this are outside the classical Roman system.
MMXXVI = 2026. MM = 2000, XX = 20, VI = 6.
Yes — use the Roman to Arabic mode by toggling the conversion direction.
The ancient Romans had no concept of zero in their numeral system. Zero was introduced to Europe later via Arabic mathematics.
Super Bowl 60 would be Super Bowl LX (L=50, X=10).
Yes — completely free with no sign-up.
Related Tools
Number to Words Converter – Convert Numbers Free Online
Convert any number to English words online—standard, ordinal, or currency format. Supports numbers up to trillions. Instant, browser-based, and free.
Percentage Calculator
Calculate percentages, growth rates, and proportions online with our Percentage Calculator. Instantly solve math problems for finance, shopping, school, or data analysis—fast, accurate, and browser-based.
Free Case Converter Online - Convert Text to Uppercase, Lowercase, Title Case
Instantly convert text between UPPERCASE, lowercase, Title Case, and more online with our Case Converter & Text Formatter. Clean and format your content for publishing, coding, or social media—fast, secure, and browser-based with no data saved.
Free Word Counter Online - Count Words, Characters, Sentences
Count words, characters, and sentences in real-time online with our Word Counter & Text Analyzer. Instantly analyze your text for SEO, writing, or academic needs—secure, private, and lightning-fast. No limits, no registration, and works on any device.
Unit Converter
Convert length, weight, and temperature units online instantly with our Unit Converter. Switch between metric and imperial units for science, cooking, or travel—fast, accurate, and works offline.
Age Calculator
Calculate your exact age in years, months, and days online with our Age Calculator. Instantly see a detailed breakdown of your age, including leap years and lifetime statistics—perfect for personal, legal, or educational use. No registration, no data stored.