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Roman Numeral Converter

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Convert numbers to Roman numerals and Roman numerals to numbers.

Roman numeral
MMXXIV
Symbol breakdown
M1000
M1000
X90
X90
I9
V5
Roman numeral symbols

What is Roman Numeral Converter?

A Roman Numeral Converter transforms standard Arabic numbers (1, 2, 3...) into Roman numerals (I, II, III...) and vice versa. Roman numerals use combinations of the letters I, V, X, L, C, D, and M to represent numbers. They are still used today for clock faces, movie sequels, book chapters, sporting events like the Super Bowl, and formal inscriptions.

Why use Nuo Tools's Roman Numeral Converter?

Bidirectional
Convert Arabic numbers to Roman numerals and back.
Step-by-step
Shows how the Roman numeral is constructed symbol by symbol.
Validation
Highlights invalid Roman numeral input with an error message.
Reference table
Built-in Roman numeral symbol reference chart.

How to use Roman Numeral Converter

1

Enter an Arabic number (1–3,999) to convert it to Roman numerals.

2

Or enter a Roman numeral (e.g. XLII) to convert it to an Arabic number.

3

The conversion appears instantly.

4

Click Copy to copy the result to your clipboard.

Frequently asked questions

What are the basic Roman numeral symbols?+

I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1000. Combinations are formed by addition (VI = 6) and subtraction when a smaller value precedes a larger one (IV = 4, IX = 9, XL = 40, XC = 90, CD = 400, CM = 900).

What is the largest number in Roman numerals?+

The standard Roman numeral system represents numbers from 1 to 3,999. The number 3,999 is written as MMMCMXCIX. Numbers 4,000 and above require overlines or extensions to the standard system that are not universally used.

Why can't you have four of the same symbol in a row?+

Roman numeral rules state that you cannot repeat a symbol more than three times consecutively. Instead of IIII for 4, you write IV (5 minus 1). This rule keeps Roman numerals concise and readable. However, some traditional clock faces use IIII for 4 instead of IV.

Are Roman numerals still used today?+

Yes. Roman numerals appear on clock faces (I–XII), in movie and TV series sequel numbering (Star Wars: Episode IV), book preface pages (i, ii, iii), Olympic Games (XXXIII Olympiad), Super Bowl numbering, chapter headings in formal documents, and year inscriptions on buildings and memorials.

When to use this tool

  • Understanding Roman numerals on clocks, monuments, or historical documents
  • Writing dates in Roman numeral format for formal documents or design
  • Converting chapter or section numbers in formal writing or academic papers
  • Learning Roman numeral rules for school or for fun
About this tool
CategoryEducation Tools
PlatformBrowser (client-side)
CostFree forever
Account requiredNo
Data storedNone
Works offlineYes
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