Converters
Roman Numeral Converter
Convert between decimal numbers and standard Roman numerals.
Number to Roman numeral
Roman numeral to number
About This Tool
Convert ordinary decimal whole numbers to standard Roman numeral notation, or check a Roman numeral and convert it back to a decimal value. The tool follows the conventional modern forms used for values from 1 through 3999 and rejects nonstandard combinations instead of silently assigning them a misleading value.
How To Use It
- For number-to-Roman conversion, enter a whole number from 1 through 3999.
- For Roman-to-number conversion, enter a standard numeral using I, V, X, L, C, D, and M.
- Read or copy the result. Lowercase Roman input is accepted and interpreted case-insensitively.
- If a Roman form is nonstandard, use the validation message to correct its subtractive or repetition pattern.
Examples
14 = XIV
X represents 10 and IV represents 4, giving XIV = 14.
944 = CMXLIV
CM is 900, XL is 40, and IV is 4, so CMXLIV represents 944.
1994 = MCMXCIV
M + CM + XC + IV gives 1000 + 900 + 90 + 4 = 1994.
Useful Notes
Roman numeral symbols
The seven basic symbols are I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, and M = 1000. Most values are written by placing symbols from larger to smaller and adding them.
Standard subtractive pairs
Modern conventional notation uses six common subtractive pairs: IV = 4, IX = 9, XL = 40, XC = 90, CD = 400, and CM = 900. Forms such as IL for 49 or IC for 99 are rejected; 49 is XLIX and 99 is XCIX.
Why the range stops at 3999
Plain Roman letters have a widely recognized canonical form through MMMCMXCIX (3999). Larger historical or modern representations can use overlines or other conventions that are not reliably represented by ordinary text, so this tool keeps one clear notation system.
No Roman numeral for zero in this convention
Classical Roman numeral notation did not use the same positional zero concept as the decimal system. This converter therefore starts at 1 rather than inventing a zero symbol.
Validation is intentionally strict
Some informal inscriptions and historical texts use variant forms. This converter targets the standard modern canonical notation used in common educational and reference contexts, so equivalent but noncanonical spellings are not accepted.
FAQ
What is 2026 in Roman numerals?
2026 is MMXXVI: MM = 2000, XX = 20, and VI = 6.
Can I write 4 as IIII?
IIII appears in some historical and clock-face contexts, but this converter uses standard modern canonical notation and writes 4 as IV.
Why is IL rejected for 49?
I may subtract only from V or X in standard notation. Forty-nine is written XLIX: XL = 40 and IX = 9.
Does the converter support numbers above 3999?
No. Larger Roman numeral conventions require notation such as overlines or other extensions, so the tool deliberately limits itself to the unambiguous standard text range 1–3999.
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