Roman Numeral Converter
Convert a number to Roman numerals or decode a Roman numeral back to a number. Standard notation is supported for values from 1 to 3,999.
Roman numerals for nearby years
Roman numeral symbols and rules
The seven symbols are I (1), V (5), X (10), L (50), C (100), D (500), and M (1,000). A smaller symbol before a larger one indicates subtraction, as in IV (4), IX (9), XL (40), and CM (900). The standard converter accepts canonical forms from I through MMMCMXCIX.
Frequently asked questions
What range can I convert?
The converter supports standard Roman numerals for whole numbers from 1 to 3,999.
Can I convert Roman numerals back to numbers?
Yes. Enter a numeral using I, V, X, L, C, D, and M, then choose Convert to number. Non-standard forms are rejected.
Why is a form like IIII invalid?
Standard modern notation uses subtractive pairs such as IV for 4 and IX for 9. The converter checks that the numeral matches the standard form.
Does the converter send my input anywhere?
No. Conversion happens in your browser.