Roman Numeral Converter
Number to Roman Numeral
Result
| Roman Numeral | — |
|---|
Roman Numeral to Number
Result
| Standard Number | — |
|---|
How to Use This Roman Numeral Converter
Roman numerals pop up on clock faces, movie credits, book chapters, and outline headings—then you are suddenly trying to remember whether XL means 40 or 60. This converter handles both directions: turn any integer from 1 to 3,999 into standard Roman numerals, or decode a Roman string back to a regular number.
- Number to Roman Numeral — enter Enter Number (1–3999). Type an integer such as 2024.
- Press Convert to Roman. Read Roman Numeral in the result table.
- Roman Numeral to Number — enter Enter Roman Numeral. Type the numeral (case-insensitive), e.g. MMXXIV.
- Press Convert to Number. Review Standard Number in the result table. Invalid forms show an error message below the input.
For general integer math or percentage problems, use calculators elsewhere on the site. For historical dates beyond 3,999, consult references on vinculum (overbar) notation not supported here.
Roman Numeral Converter Formulas and Practical Applications
Roman numerals build from seven symbols: I (1), V (5), X (10), L (50), C (100), D (500), M (1000). Encoding uses greedy subtraction—larger composite symbols first.
Subtractive pairs: CM = 900, CD = 400, XC = 90, XL = 40, IX = 9, IV = 4. Decoding reads left to right: if a symbol is smaller than the next, subtract it; otherwise add it. Example: MMXXIV → M(1000) + M(1000) + X(10) + X(10) + IV(4) = 2024.
Standard notation stops at 3,999 (MMMCMXCIX). Larger ancient numbers used a vinculum (overbar) for ×1000, which standard text encoding does not support here.
Symbol Reference
- I = 1, V = 5, X = 10, L = 50
- C = 100, D = 500, M = 1000
- Max standard value: MMMCMXCIX = 3999
Frequently Asked Questions
Why can't I convert numbers above 3,999?
Classical Roman numerals without overbar notation max out at MMMCMXCIX (3,999). Larger values historically used special notation not representable in plain ASCII text.
Is IV the same as IIII on clocks?
Both represent 4. Many analog clocks use IIII instead of IV for visual balance. This converter outputs standard subtractive form (IV), but accepts common variants when decoding if they follow valid patterns.
Why was my Roman numeral rejected?
The decoder validates strict standard form. Invalid repeats (like VV for 10 instead of X) or wrong subtractive pairs (IL instead of XLIX) return an error. Check that only I, V, X, L, C, D, M appear and subtractive rules are followed.
Are Roman numerals case-sensitive when decoding?
No. Enter Roman Numeral input is treated case-insensitively—mmxxiv and MMXXIV both decode to 2024.
What number range works for Number to Roman Numeral?
Integers from 1 to 3,999 inclusive. Values outside that range are rejected by the form validation.