Roman Numeral Converter
Convert numbers to Roman numerals and Roman numerals back to numbers, both ways, from 1 to 3999 — with instant validation.
Convert
Type a number to see it in Roman numerals.
The Roman Numeral Converter translates ordinary numbers into Roman numerals and reads Roman numerals back into numbers, both directions, for values from 1 to 3999. It is handy for dates on buildings and movie credits, clock faces, book chapters, Super Bowl numbers, and homework, and it checks that what you type is a valid numeral.
How to use the Roman Numeral Converter
- Choose a direction: Number → Roman or Roman → Number.
- Type your number (1 to 3999) or a Roman numeral such as MMXXVI.
- Read the converted result, which updates as you type.
- Copy or share the result in one tap.
Frequently asked questions
- What is the largest number I can convert?
- Standard Roman numerals go up to 3999, written MMMCMXCIX. Larger values historically used a bar over letters to multiply by 1000, which is not part of everyday notation, so this tool covers 1 through 3999.
- Why is 4 written as IV and not IIII?
- Roman numerals use subtractive notation, where a smaller symbol before a larger one means subtract, so 4 is IV (5 minus 1) and 9 is IX (10 minus 1). The converter always produces this standard modern form.
- Does it accept lowercase Roman numerals?
- Yes. You can type numerals in lowercase or uppercase, such as mmxxvi or MMXXVI, and the tool reads both and displays the result in uppercase.
- How do I write the current year in Roman numerals?
- Switch to Number → Roman and enter the year. For example, 2026 becomes MMXXVI: two thousands (MM), twenty (XX), five (V), and one (I).