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🏛️ Roman Numeral Converter - Complete Guide

Last updated: October 2025 | Reading time: 6 minutes

What are Roman Numerals?

Roman numerals are an ancient number system developed in Rome, used throughout the Roman Empire. Unlike our modern decimal system, Roman numerals use letters from the Latin alphabet to represent values.

Still used today for:

  • Clock faces and watches
  • Book chapters and volumes
  • Movie sequels and series (Rocky IV, Super Bowl LVIII)
  • Formal documents and monuments
  • Outlines and lists
  • Copyright years in films

Roman Numeral Symbols

Basic Symbols:

  • I = 1
  • V = 5
  • X = 10
  • L = 50
  • C = 100
  • D = 500
  • M = 1000

Common Combinations:

  • I = 1, II = 2, III = 3
  • IV = 4, V = 5, VI = 6, VII = 7, VIII = 8, IX = 9
  • X = 10, XX = 20, XXX = 30
  • XL = 40, L = 50, LX = 60, LXX = 70, LXXX = 80, XC = 90
  • C = 100, CC = 200, CCC = 300
  • CD = 400, D = 500, DC = 600, DCC = 700, DCCC = 800, CM = 900
  • M = 1000, MM = 2000, MMM = 3000

Conversion Rules

Addition Rule:

When a smaller symbol appears after a larger one, add the values.

  • VI = 5 + 1 = 6
  • XII = 10 + 1 + 1 = 12
  • LXV = 50 + 10 + 5 = 65

Subtraction Rule:

When a smaller symbol appears before a larger one, subtract the smaller from the larger.

  • IV = 5 - 1 = 4
  • IX = 10 - 1 = 9
  • XL = 50 - 10 = 40
  • XC = 100 - 10 = 90
  • CD = 500 - 100 = 400
  • CM = 1000 - 100 = 900

Repetition Rule:

A symbol can be repeated up to 3 times to add value.

  • III = 1 + 1 + 1 = 3
  • XXX = 10 + 10 + 10 = 30
  • CCC = 100 + 100 + 100 = 300

Note: V, L, and D are never repeated.

Subtraction Limitations:

  • Only I, X, and C can be subtracted
  • Only from the next two higher values
  • I can be subtracted from V and X only
  • X can be subtracted from L and C only
  • C can be subtracted from D and M only

How to Use the Roman Numeral Converter

Arabic to Roman:

  1. Enter a number from 1 to 3999
  2. Click "Convert to Roman"
  3. See the Roman numeral result

Roman to Arabic:

  1. Enter Roman numerals (I, V, X, L, C, D, M)
  2. Click "Convert to Arabic"
  3. See the numeric result

Example:

Input: 1994

Output: MCMXCIV

Breakdown: M (1000) + CM (900) + XC (90) + IV (4)

Common Use Cases

1. Education & History

  • Learning ancient Roman culture
  • History homework and research
  • Understanding historical dates on monuments
  • Reading ancient texts and inscriptions

2. Document Formatting

  • Book chapters and sections (Chapter IV)
  • Outlines and lists (I, II, III, IV)
  • Legal documents and contracts
  • Academic papers and theses

3. Entertainment & Media

  • Movie sequels (Star Wars Episode IV)
  • Super Bowl numbers (Super Bowl LVIII)
  • Copyright years in film credits
  • Video game titles (Final Fantasy VII)

4. Design & Architecture

  • Clock and watch faces
  • Building cornerstones and plaques
  • Monument inscriptions
  • Decorative elements

5. Formal Events

  • Wedding invitations
  • Anniversary celebrations
  • Graduation years
  • Commemorative items

Conversion Examples

Years:

  • 2024 = MMXXIV
  • 2000 = MM
  • 1999 = MCMXCIX
  • 1776 = MDCCLXXVI
  • 1492 = MCDXCII

Common Numbers:

  • 1 = I, 2 = II, 3 = III, 4 = IV, 5 = V
  • 6 = VI, 7 = VII, 8 = VIII, 9 = IX, 10 = X
  • 11 = XI, 12 = XII, 13 = XIII, 14 = XIV, 15 = XV
  • 20 = XX, 30 = XXX, 40 = XL, 50 = L
  • 100 = C, 500 = D, 1000 = M

Super Bowl Numbers:

  • Super Bowl 50 = Super Bowl L
  • Super Bowl 54 = Super Bowl LIV
  • Super Bowl 58 = Super Bowl LVIII

Movie Titles:

  • Rocky IV = Rocky 4
  • Star Wars Episode VI = Star Wars Episode 6
  • Final Fantasy VII = Final Fantasy 7

Frequently Asked Questions

Q: Why is there no zero in Roman numerals?

A: The concept of zero as a number didn't exist in ancient Rome. Roman numerals were used for counting, not mathematics.

Q: What's the largest number in Roman numerals?

A: Standard Roman numerals go up to 3999 (MMMCMXCIX). Larger numbers used special notation with bars over letters.

Q: Why is 4 written as IV and not IIII?

A: Both were used historically. IV (subtractive notation) became standard, though IIII still appears on some clock faces.

Q: Can you write 1999 as MIM?

A: No. The correct form is MCMXCIX. You can only subtract I from V or X, not from M.

Q: How do you write fractions in Roman numerals?

A: Romans had special symbols for fractions (S for 1/2, etc.), but these aren't commonly used today.

Q: Why do some clocks use IIII instead of IV?

A: Tradition and aesthetics. IIII balances VIII on the opposite side and was used in early sundials.

Q: Can Roman numerals be lowercase?

A: Traditionally uppercase, but lowercase (i, v, x, etc.) is sometimes used in modern contexts like page numbering.

Why Use Our Roman Numeral Converter?

  • ✅ Bidirectional: Convert both ways instantly
  • ✅ 100% Accurate: Follows all Roman numeral rules
  • ✅ Range 1-3999: Covers all standard Roman numerals
  • ✅ Instant Results: No waiting, immediate conversion
  • ✅ Free Forever: No registration needed
  • ✅ Educational: Learn Roman numeral rules
  • ✅ Mobile Friendly: Works on all devices
  • ✅ Easy to Use: Simple, clear interface

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