Roman Numeral Converter Online — Numbers to Roman Numerals
Convert integers from 1 to 3999 into Roman numerals or valid Roman numerals back to integers.
About this tool
Numeric input is encoded with canonical Roman symbols. Text input is parsed and checked by converting back to its canonical representation.
How to use
- Enter or select the required input.
- Run the tool with the intended options.
- Review the result before using or downloading it.
Features
- Two-way conversion.
- Canonical subtractive notation.
- Strict Roman validation.
Common use cases
- Read dates and chapter numbers.
- Create outline labels.
- Check Roman numeral exercises.
Common issues and tips
- Integer conversion supports 1–3999.
- Noncanonical forms such as IIII are rejected.
Privacy
Processing runs locally in your browser. Input is not uploaded to Tools12345.
Frequently asked questions
What range is supported?
1 through 3999.
Is lowercase accepted?
Input is normalized to uppercase.
Is IIII valid?
No, canonical four is IV.