Roman Numeral Converter

How to Convert Numbers to Roman Numerals

Roman numerals use seven letters from the Latin alphabet to represent values. To convert an Arabic number to Roman numerals, repeatedly subtract the largest possible Roman numeral value from the number, appending the symbol each time.

Example — 2024: 2024 → M(1000) → M(1000) → X(10) → X(10) → IV(4) = MMXXIV

Example — 1776: 1776 → M(1000) → D(500) → C(100) → C(100) → L(50) → X(10) → X(10) → V(5) → I(1) = MDCCLXXVI

Subtractive Notation Rules

Roman numerals use subtractive notation for four values: 4, 9, 40, 90, 400, and 900. Instead of writing IIII for 4, Romans wrote IV (5 minus 1). The rules are:

• I can precede V (IV = 4) and X (IX = 9)
• X can precede L (XL = 40) and C (XC = 90)
• C can precede D (CD = 400) and M (CM = 900)
• A numeral can only be subtracted from the next two higher values (I only from V and X, not L, C, D, or M)
• Only one numeral can be subtracted at a time (IIX for 8 is wrong; VIII is correct)

These conventions were standardized in medieval manuscripts and are used in all modern contexts, from clock faces to book chapters to Super Bowl numbering.

Roman Numeral Reference Chart: 1 to 100

Memorizing key values is the fastest way to read Roman numerals fluently. Here is the complete reference for 1–100:

Hundreds and Thousands: 100 to 3999

Understanding the hundreds and thousands makes any large number readable:

The standard Roman numeral system only goes up to 3,999 (MMMCMXCIX). Numbers above 3,999 require a vinculum (a bar over a numeral multiplying its value by 1,000), but this is rarely used in modern applications.

Where Roman Numerals Are Used Today

Roman numerals remain in active use across many modern contexts:

• Super Bowl numbering: The NFL has used Roman numerals since Super Bowl V (1971). Super Bowl LVIII was played in 2024.
• Clock faces: Most analog clock faces with Roman numerals use IIII for 4 (rather than IV) — a historical convention dating to clockmaking traditions, likely because IV resembles the first two letters of "IVPITER" (Jupiter).
• Book chapters and outlines: Chapter I, II, III… or outline headings I, II, III, A, B, C.
• Movie sequels and series: Rocky II, Star Wars Episode VI, The Godfather Part II.
• Copyright and production years: Films and TV shows often display the production year in Roman numerals in end credits.
• Monarchs and popes: King Charles III, Pope Francis (the current pope; his predecessor was Benedict XVI).
• Olympic Games: The XXXIII Summer Olympics will be held in Los Angeles in 2028.
• Architecture and monuments: Cornerstones, dedications, and memorial inscriptions commonly use Roman numerals.

History of Roman Numerals

Roman numerals developed from ancient tally marks used in early Rome and the Etruscan civilization around 900–800 BCE. The symbols likely evolved as follows:

• I represents a single tally mark — a vertical stroke (from finger-counting or notched sticks)
• V represents an open hand (five fingers) — the V shape formed when the thumb is spread
• X represents two Vs crossing — a double hand, or simply two groups of five
• L, C, D, M were adopted from Etruscan symbols and later associated with Latin words (C = centum = 100, M = mille = 1000)

Roman numerals dominated Western mathematics for over a thousand years. Their replacement by Hindu-Arabic numerals (0–9) began in the 12th century, largely through Italian merchants who adopted the system from Arab traders who had learned it from Indian mathematicians. Leonardo Fibonacci's Liber Abaci (1202) popularized Hindu-Arabic numerals in Europe, and by the 15th century they had largely replaced Roman numerals for calculation. Roman numerals survived in ceremonial and decorative use where they remain today.