Roman Numeral Converter
Convert between numbers and Roman numerals in either direction — type 1994 or MCMXCIV and the tool detects which way to go.
Processed locally in your browser — nothing is uploaded.
Roman Numeral Converter
The direction is detected automatically. Valid range: 1–3999.
Enter a number like 1994 or a numeral like MCMXCIV.
About Roman Numeral Converter
One input, both directions: digits convert to a Roman numeral, letters convert back to a number. Standard subtractive notation is enforced, so IIII or VX are rejected with a clear message instead of a wrong answer. The supported range is 1 to 3999, the limit of classic notation.
Common uses
- Decode the year in a film's credits or on a building
- Write a date or chapter number in Roman numerals
- Check homework answers in both directions
Example
Input
1994
Output
MCMXCIV
Limitations
- Numbers above 3999 need overline notation, which plain text can't represent
Frequently asked questions
Why do Roman numerals stop at 3999?
M (1000) is the largest standard symbol and convention allows at most three in a row, so MMMCMXCIX (3999) is the ceiling. Larger numbers used a vinculum — an overline multiplying a numeral by 1,000 — which plain text can't represent, so this converter enforces the 1–3999 range.
Is IIII a valid Roman numeral for 4?
Not in standard subtractive notation, where 4 is written IV. IIII survives mainly on clock faces as a traditional exception; this converter follows the strict rules and rejects IIII with an error rather than guessing.
How does subtractive notation work?
A smaller numeral placed before a larger one is subtracted instead of added: IV is 4, IX is 9, XL is 40, XC is 90, CD is 400, CM is 900. Only those six pairs are allowed, which is why VX for 5-minus-10 style shortcuts is invalid.
Is there a Roman numeral for zero?
No. The Roman system had no symbol for zero — medieval scribes sometimes wrote the word "nulla" — which is why the valid range starts at 1.
Does the conversion happen on my device?
Yes. Both directions are computed locally in your browser with no network request, so the tool works offline once loaded and nothing you enter is sent anywhere.