This Roman numeral converter works both ways: turn any number from 1 to 3,999 into Roman numerals, or decode a Roman numeral back into a number — with the subtractive rules (IV, IX, CM) handled correctly.
The Roman Numerals
| Symbol | I | V | X | L | C | D | M |
|---|---|---|---|---|---|---|---|
| Value | 1 | 5 | 10 | 50 | 100 | 500 | 1,000 |
Numbers are built left to right, largest first, with one twist — the subtractive rule: a smaller symbol just before a larger one subtracts (IV = 4, IX = 9, XL = 40, XC = 90, CD = 400, CM = 900). Only I, X and C may subtract, only one step up, and no symbol repeats more than three times. This converter lives in our Other Calculators collection.
Worked Examples (Verified)
- 2026 → MMXXVI (MM = 2000, XX = 20, VI = 6)
- 1994 → MCMXCIV (M = 1000, CM = 900, XC = 90, IV = 4 — three subtractive pairs in one number)
- 3888 → MMMDCCCLXXXVIII — the longest numeral under 4000, fifteen symbols
- Super Bowl numbers, book chapters, copyright years (MMXXVI on a film) and clock faces are where you still meet them daily.
Curiosities and Limits
- No zero, no negatives, no fractions as such — Rome counted what it could point at; the absence of zero is one reason Roman arithmetic stayed clumsy and positional notation won.
- Clocks often use IIII instead of IV — a traditional watchmaker’s exception (visual balance against VIII), correct by convention, “wrong” by the strict rules this converter enforces.
- Beyond 3,999, a bar over a numeral (vinculum) multiplies it by 1,000 — V̅ = 5,000. Classical inscriptions rarely needed it.
- For the arithmetic Rome wished it had, see our Math Calculators.
Related Tools
- Binary Converter — another numeral system, the computer’s
- Other Calculators — the full collection
Frequently Asked Questions
How do you write 2026 in Roman numerals?
MMXXVI: 2000 (MM) + 20 (XX) + 6 (VI).
What is MCMXCIV?
1994 — M (1000) + CM (900) + XC (90) + IV (4). It appears in the credits of films from that era, the golden age of Roman-numeral copyright dates.
Why is 4 written IV and not IIII?
The subtractive convention avoids four repeats. Clock faces are the famous exception, often using IIII for symmetry with VIII.
What is the largest Roman numeral?
In standard form, 3,999 (MMMCMXCIX). Larger values historically used overlines (vincula) multiplying by 1,000.
How do you read a Roman numeral quickly?
Scan left to right, adding each symbol — except when a smaller symbol precedes a larger one, in which case subtract the pair’s difference. Convert above and check yourself.
Is this Roman numeral converter free?
Yes — free, instant, no sign-up.