Math & Education
Roman Numeral Converter
Convert standard Roman numerals and decimal numbers both ways.
Your inputs
Adjust the values
Convert standard Roman numerals or whole numbers from 1 through 3,999. Nonstandard forms are rejected.
Roman numeral
MMXXVI
About this tool
A straightforward roman numeral converter
Convert standard Roman numerals and decimal numbers both ways. Decimal values use standard subtractive notation, and entered numerals are validated by converting them back to canonical form.
The converter accepts standard modern notation and rejects ambiguous or noncanonical sequences. Inputs are processed in your browser, and changing a value updates the result immediately.
How it works
Use the Roman Numeral Converter in three steps
- 1Enter your values
Enter a whole number from 1 to 3,999 or a Roman numeral.
- 2Check the setup
Choose the units or calculation mode that matches your situation.
- 3Use the result
See both the canonical Roman numeral and decimal value.
Common questions
Roman Numeral Converter FAQ
How does the Roman Numeral Converter work?
Decimal values use standard subtractive notation, and entered numerals are validated by converting them back to canonical form.
What information do I need?
Enter a whole number from 1 to 3,999 or a Roman numeral.
How accurate is the result?
The converter accepts standard modern notation and rejects ambiguous or noncanonical sequences.