How do Roman numerals work?

Seven symbols carry values — I=1, V=5, X=10, L=50, C=100, D=500, M=1000 — combined additively left to right, except when a smaller symbol precedes a larger one, which subtracts: IV=4, IX=9, XL=40, XC=90, CD=400, CM=900.

What are the subtraction rules?

Only I, X, and C may be subtracted, and only from the next two larger symbols: I before V/X, X before L/C, C before D/M. IL for 49 is invalid — correct is XLIX.

What is 2026 in Roman numerals?

MMXXVI — MM (2000) + XX (20) + VI (6). Year conversion for movies, monuments, and copyright lines is the most common everyday use.

Is there a Roman numeral for zero or large numbers?

Classical Roman numerals have no zero. Numbers above 3,999 traditionally use a vinculum (overline) multiplying a symbol by 1,000 — V̄ is 5,000; the converter supports extended notation.

Why is 4 sometimes IIII on clocks?

Clock faces traditionally use IIII instead of IV for visual balance with VIII on the opposite side — a stylistic convention, not standard notation.

Roman Numeral Converter — Numbers to Roman & Back, Free...

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Roman Numeral Converter — MCMXCIV Made Instant

Decoding the year at the end of a film's credits, numbering book chapters, engraving a date, or checking Super Bowl LVIII's number — Roman numerals persist everywhere formality lives. This free converter translates both directions instantly, validates against the classical rules, and shows the symbol-by-symbol breakdown so the logic is visible. In-browser, no signup.

The Symbol Set and Subtraction Pairs

Symbol	Value	Subtractive pair	Value
I	1	IV / IX	4 / 9
V	5	XL / XC	40 / 90
X	10	CD / CM	400 / 900
L	50	Only these six subtractive combinations are valid.
C	100
D / M	500 / 1000

Worked Example: 1994 → MCMXCIV

Decompose by place value: 1000 (M) + 900 (CM) + 90 (XC) + 4 (IV). Each digit maps independently — which is exactly the algorithm the converter runs, and why reading long numerals is easiest in chunks: M | CM | XC | IV.

Recent and Upcoming Years

MMXX (2020) · MMXXV (2025) · MMXXVI (2026) · MMXXX (2030) · MML (2050) · MMC (2100). Copyright lines, cornerstones, and film credits use exactly these forms.

Validity Matters

Common invalid forms the tool catches: IIII (use IV — except on clock faces), IL (49 is XLIX), VX (5 can't be subtracted), MIM (1999 is MCMXCIX). Repetition is limited to three of the same symbol; V, L, and D never repeat or subtract.

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Roman Numeral Converter

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