Roman Numeral Converter

Convert Arabic numbers and Roman numerals both ways

Arabic number

Roman numeral

About This Tool

Roman Numeral Converter converts Arabic integers (1–3999) to classic Roman numerals and back. Invalid values show a visible error. Processed locally in your browser — no upload needed.

How to Use

Enter an Arabic number or Roman numeral
Click the conversion direction
Review the result
Copy if needed
Clear to start over

Common Use Cases

Outline numbering
Clock and chapter labels
Homework checks
Historical notes
Typography experiments

FAQ

Q1: What range is supported?

Arabic integers from 1 to 3999 using classic Roman notation.

Q2: Are subtractive forms required?

Yes. Valid output uses standard forms like IX and XL.

Q3: Is data uploaded?

No. Everything runs locally in your browser.

Q4: What about empty input?

You will see a visible prompt to enter a value.

Q5: Can I convert both ways?

Yes. Use To Roman or To Arabic.

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