Roman Numeral Converter
Convert any whole number from 1 to 3999 into a Roman numeral, or any Roman numeral back into a decimal. Strict canonical form (MCMXCIV, not MDCCCCLXXXXIIII).
1994 in Roman numerals
MCMXCIV
- M
- 1,000
- CM
- 900
- XC
- 90
- IV
- 4
MCMXCIV = M + CM + XC + IV = 1000 + 900 + 90 + 4
How to use this calculator
Choose a direction: "Decimal → Roman" to turn a number into Roman numerals, or "Roman → Decimal" to read an existing numeral. Type your value in the input — for Roman, any of I V X L C D M (any case). The result and place-value breakdown update as you type.
How the calculation works
Roman numerals use seven symbols: I=1, V=5, X=10, L=50, C=100, D=500, M=1000. The canonical form repeats each symbol up to three times and uses six subtractive pairs — IV (4), IX (9), XL (40), XC (90), CD (400), CM (900) — to avoid four-in-a-row. The encoder runs a greedy walk down the value table [M, CM, D, CD, C, XC, L, XL, X, IX, V, IV, I], emitting each symbol while it still fits. The decoder scans left to right and subtracts any symbol smaller than the one to its right, then round-trips through the encoder to reject non-canonical inputs like IIII or IC.
Worked example
1994 → M (1000) leaves 994 → CM (900) leaves 94 → XC (90) leaves 4 → IV (4) leaves 0. Result: MCMXCIV. Decoding the same string: M(1000) + C<M so −100 + M=900 → 1900, + X<C so −10 + C=90 → 1990, + I<V so −1 + V=4 → 1994.
Frequently asked questions
Why stop at 3999?
Classical Roman numerals have no symbol for zero and no agreed extension above 3999 — to go higher you needed a vinculum (overline) multiplying a numeral by 1000, which the Romans wrote inconsistently and which no longer renders cleanly in plain text. Modern style guides (Chicago Manual of Style, the Unicode standard) treat 3999 as the practical upper bound.
What about IIII on clock faces?
Clock face IIII is a stylistic exception, not standard notation. The convention dates to medieval clockmaking — partly for visual symmetry with the VIII opposite it, partly so the mould only needed to cast four I shapes per clock. This calculator outputs IV, the canonical form.
Is there a zero in Roman numerals?
No. The Romans had no positional system and no need for zero as a placeholder. Medieval European arithmetic used the word "nulla" (Latin for "none") when a zero was needed in a table. Zero entered Europe with the Hindu-Arabic numerals around the 12th century.
Why is IC for 99 not allowed?
Subtractive notation is restricted to the six pairs IV, IX, XL, XC, CD, CM — each subtracts a power of ten from the next-but-one symbol up. IC would subtract 1 from 100, skipping V, X, L. The standard form for 99 is XCIX (XC + IX = 90 + 9).
Are Roman numerals case sensitive?
No. Classical inscriptions used majuscule (capital) letters because that was the only Latin alphabet. Modern lowercase forms (mcmxciv) are common in book pagination and outline numbering. This converter accepts either case and returns uppercase.
How are Roman numerals still used today?
Clock faces, book chapters and prefaces, monarchs and popes (Elizabeth II, Pope Francis I), Super Bowl numbering, film copyright dates, building cornerstones, outline lists (I, II, III), and chemistry oxidation states (Fe(III)). They survive where decimal numerals would feel too plain.