Encoding & character sets
Roman Numeral Converter
Convert a number to Roman numerals and Roman numerals to a number, from 1 to 3,999 (up to 3,999,999 with the bar), with strict validation and an explanation of wrong forms.
How to use this tool
- 1
Enter a number or Roman numerals (or load the example).
- 2
Read the conversion and its breakdown.
- 3
Fix the form if an error message offers the standard one.
- 4
Copy the result.
Help
- Type a number (1994) or Roman numerals (MCMXCIV): the tool guesses the direction. Arabic-Indic digits (١٩٩٤) and Unicode Roman letters (Ⅻ) are understood, and I V X L C D M keys make typing easy on a phone.
- Validation is strict: “IIII” is rejected and the tool tells you to write “IV”; “VX”, “IC” or “IIX” are flagged as impossible. Reminder: I, X, C and M repeat at most three times, V, L and D never, and only I, X and C are subtracted.
- Beyond 3,999, extended notation puts a bar over letters to multiply them by 1,000 (V̅ = 5,000, M̅ = 1,000,000); it goes up to 3,999,999 and can be switched off with one click.
- The breakdown shows how the number is built (MCMXCIV = M + CM + XC + IV = 1000 + 900 + 90 + 4). There is no zero or negative number in Roman numerals.
Frequently asked questions
Why is 4 written IV and not IIII?
The modern rule forbids more than three identical letters in a row and prefers subtraction: IV for 4, IX for 9, XL for 40. Some clock faces still use IIII by tradition, but the tool rejects that form to stay with the standard.
How do I write a number above 3,999?
With the bar: a bar over a letter multiplies it by 1,000. 4,000 is I̅V̅ and 1,000,000 is M̅. The tool reads and produces this notation up to 3,999,999.
Is my text sent anywhere?
No, the conversion runs entirely in your browser.
Written and verified by the MaxyTools team · Updated on
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