Roman Numeral Converter

Convert between Arabic numbers and Roman numerals instantly in both directions.

XIV

Roman Numeral Converter

Arabic Number (1 – 3,999)

Examples:

How to Use

Choose conversion direction

Select Arabic-to-Roman or Roman-to-Arabic depending on which form you need to convert.

Enter Arabic numerals (1-3999)

For Arabic-to-Roman, type any whole number from 1 to 3,999.

Or enter Roman numeral letters

For Roman-to-Arabic, type the Roman numeral string using I, V, X, L, C, D, M.

Copy and use the result

Paste the converted value into clock faces, document outlines, movie credits, or historical references.

How Roman Numerals Work

Roman numerals use letters I, V, X, L, C, D, and M to represent values. Subtraction notation is used for 4 (IV), 9 (IX), 40 (XL), 90 (XC), 400 (CD), and 900 (CM). The system supports numbers from 1 to 3,999.

Real-World Examples & Use Cases

Clock Faces and Decorative Design

Roman numerals are used on traditional clock faces, watch dials, sundials, and decorative architectural elements. Designers and craftspeople converting hours (1-12) to Roman numerals need accurate representations — especially the controversial use of IIII versus IV on clock faces (historically, IIII was used on clock dials for visual balance, while IV is mathematically correct). This converter helps designers choose the historically appropriate form for their specific context.

Film and Television Titles

Roman numerals are the standard convention for sequel numbering in film and television: Rocky II, Star Wars Episode IV, Super Bowl LIX. Production companies, writers, and marketers converting sequel numbers to Roman numerals need to ensure accuracy. Getting a movie sequel Roman numeral wrong is highly visible — XLII versus XLIII, or XLVIII versus XLIX, are easy to confuse when constructing multi-digit numerals from individual symbols.

Academic Document Outline Numbering

Many academic papers, legal briefs, and formal reports use Roman numerals for major section headings: Part I, Chapter IV, Section XII. Legal citations use Roman numerals for law volumes and statutes. Roman numerals are also used for preliminary pages in books (table of contents, preface, acknowledgements) before the main page numbering restarts at page 1. This converter helps authors and editors number long documents accurately.

Historical Dating and Heritage Research

Inscriptions on buildings, monuments, coins, and gravestones frequently display dates in Roman numerals: MCMXLV (1945), MMXXIV (2024). Genealogists, historians, and heritage researchers encounter Roman numeral dates that must be decoded correctly. A date like MDCCCXCVIII contains six numeral groups (M, D, CCC, XC, V, III) and converts to 1898 — which requires careful parsing of subtractive notation. This converter decodes historical dates in both directions.

How It Works

Roman numeral conversion uses a symbol table and subtractive notation rules: Symbol values: I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1,000 Subtractive pairs (always a smaller symbol before a larger one): IV = 4, IX = 9, XL = 40, XC = 90, CD = 400, CM = 900 Arabic to Roman algorithm: 1. Start with the largest symbol (M = 1000) 2. Subtract value from number, append symbol to result 3. Repeat until number reaches 0 Example: 1994 1000 → M, remainder 994 900 → CM, remainder 94 90 → XC, remainder 4 4 → IV, remainder 0 Result: MCMXCIV Roman to Arabic algorithm: 1. Parse each symbol; if smaller symbol precedes larger, subtract it 2. Otherwise add it Constraints: Roman numerals only cover 1-3,999 (no zero, no fractions, no negatives).

Frequently Asked Questions

Why do some clock faces use IIII instead of IV for 4?▼

This is a long-standing tradition in clockmaking, not a mathematical convention. Theories include: visual symmetry (IIII balances VIII across the dial), historical preference of medieval craftsmen, and the desire to avoid confusion with king Louis IV's name. Strictly, IV is the mathematically correct Roman numeral for 4. Both forms are acceptable depending on context — traditional clocks use IIII; academic and formal numbering uses IV.

What numbers cannot be represented in Roman numerals?▼

Roman numerals cannot represent: zero (there is no symbol for it), fractions (no decimal notation), negative numbers, and numbers above 3,999 without special extensions. The Romans used a vinculum (bar over a symbol) to multiply by 1,000, allowing representation of very large numbers, but this is rarely used today. Standard Roman numeral systems strictly cover 1 to 3,999.

Are there any incorrect Roman numeral sequences to avoid?▼

Yes. Valid subtractive notation only allows specific pairs: IV (not IIV), IX (not IIX), XL (not XXL as subtractive), XC, CD, CM. You cannot repeat V, L, or D (they cannot appear more than once). I, X, C, M may repeat up to three times consecutively; four of the same is written using subtractive notation instead (e.g., IIII is non-standard; IV is correct).

Which year has the longest Roman numeral representation?▼

The year 1888 (MDCCCLXXXVIII) is frequently cited as the longest Roman numeral for a calendar year, requiring 13 characters. It contains M (1000) + DCCC (800) + LXXX (80) + VIII (8). In contrast, 2000 is simply MM (2 characters). Years in the range 1880-1889 consistently produce the longest Roman numeral representations.

How are Roman numerals used in modern law and government?▼

Roman numerals are widely used in legal and governmental contexts: US legislation references (Title VII of the Civil Rights Act), Super Bowl numbering, US presidential succession acts, and outline numbering in legal briefs. In the UK, Parliament uses Roman numerals in statutes. The United Nations and NATO also use Roman numerals for official event and meeting numbering. They persist because they visually distinguish numbered lists from the Arabic numbers used within the text.

Related Tools

Explore other tools in this category.

Number to Words Converter

Convert any number into its full English word representation.

Ohm's Law Calculator

Calculate voltage, current, resistance, and power using Ohm's Law and the power formula.

Percentage Calculator

Calculate percentages, increases, and decreases instantly.

LCM & GCF Calculator

Calculate the Least Common Multiple and Greatest Common Factor of numbers.

Prime Number Checker

Check if a number is prime or composite instantly.

Ratio Calculator

Simplify ratios and find decimal equivalents.