Roman Numeral Converter
Convert between numbers and Roman numerals, both directions.
I
1
V
5
X
10
L
50
C
100
D
500
M
1000
Roman numerals are built from seven symbols (I, V, X, L, C, D, M) that are combined by addition — reading left to right, add each symbol's value unless a smaller value comes before a larger one, in which case it is subtracted. This "subtractive notation" is used for four values in each order of magnitude: IV (4), IX (9), XL (40), XC (90), CD (400), and CM (900).
Standard Roman numerals represent whole numbers from 1 to 3999. There is no symbol for zero, and numbers 4000 and above require an overline notation (multiplying by 1000) that isn't part of standard ASCII text, so this converter is limited to the 1–3999 range.
Worked examples:
- 1994 → MCMXCIV (1000 + 900 + 90 + 4)
- 2026 → MMXXVI (1000 + 1000 + 10 + 10 + 5 + 1)
- 58 → LVIII (50 + 5 + 1 + 1 + 1)
Why is 4 written as IV instead of IIII?
Both forms have historically been used — IIII appears on many clock faces for visual symmetry with VIII on the opposite side. But standard modern usage (and this converter) uses subtractive notation: a smaller numeral placed before a larger one is subtracted, so IV = 5 − 1 = 4.
What is the largest number Roman numerals can represent?
Using only the standard I, V, X, L, C, D, M symbols, the largest representable number is 3999 (MMMCMXCIX). Larger numbers historically used a horizontal line (vinculum) over a numeral to multiply its value by 1000, but that notation isn't practical in plain text.
Is there a Roman numeral for zero?
No. The Romans did not have a numeral for zero — it wasn't part of their number system. Concepts of nothingness were expressed in words (nulla), not with a numeral symbol.
How do I convert a Roman numeral back to a number?
Read left to right, adding each symbol's value. If a symbol has a smaller value than the symbol immediately after it, subtract it instead of adding it. For example, in IX, I (1) comes before X (10), so it's subtracted: 10 − 1 = 9.