About this roman numeral converter
Convert between whole numbers and Roman numerals in either direction, right in your browser. Choose a direction, enter a whole number from 1 to 3,999 to get its Roman numeral, or enter a Roman numeral using the letters M, D, C, L, X, V, and I to get its numeric value; numeral input is checked against the canonical subtractive-notation form, so malformed numerals like "IIII" are rejected. Use this workspace to prepare a result you can review before putting it to use. All processing takes place on your device, without an account or an upload of your inputs. Check the examples to understand the expected output, read the limitations for the supported scope, and reset the form when you want to start a separate task.
How the roman numeral converter works
Builds the Roman numeral greedily from the largest matching value-symbol pair (M, CM, D, CD, C, XC, L, XL, X, IX, V, IV, I); the reverse direction sums symbol values, subtracting a symbol that precedes a larger one, and rejects any input that doesn't re-encode to the same numeral.
Roman Numeral Converter examples
1994
MCMXCIV
MCMXCIV
1994
Limitations & privacy
Supports the standard range of 1 to 3,999; Roman numerals have no symbol for zero or negative numbers. Only canonical subtractive-notation numerals are accepted as valid input.
Inputs and results stay in this browser. Only tool identifiers are stored for your recently used tools. You can clear that history from the directory.
Roman Numeral Converter: frequently asked questions
How does the roman numeral converter work?
Builds the Roman numeral greedily from the largest matching value-symbol pair (M, CM, D, CD, C, XC, L, XL, X, IX, V, IV, I); the reverse direction sums symbol values, subtracting a symbol that precedes a larger one, and rejects any input that doesn't re-encode to the same numeral.
What can I inspect in the roman numeral converter result?
The roman numeral decomposition helps you check the result before using it. Supports the standard range of 1 to 3,999; Roman numerals have no symbol for zero or negative numbers. Only canonical subtractive-notation numerals are accepted as valid input.
Does the roman numeral converter upload my input?
Processing happens in your browser. No tool input or output is uploaded to a server. Use Reset to clear the current workspace before starting a separate task.
Updated September 20, 2026