Roman Numeral Converter
Convert between integers and Roman numerals. Bidirectional converter with conversion steps shown.
Roman Numeral Converter
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The Roman numeral converter translates between standard integers and Roman numerals in both directions. Enter a number (1–3999) to get its Roman numeral equivalent, or enter a Roman numeral to convert it to a number. The converter also shows each step of the conversion process so you can follow the logic. Roman numerals remain in common use: clock faces often use Roman numerals, movie release years are traditionally written in Roman numerals, Super Bowl editions are numbered with Roman numerals (Super Bowl LVIII = Super Bowl 58), and chapter headings in books and legal documents frequently use Roman numeral numbering. The standard range for Roman numerals is 1–3999 (MMMCMXCIX). Numbers from 4,000 upward require additional notation (a bar over a numeral multiplies it by 1,000) which is less standardised — this converter handles the classic range only.
How to Use the Roman Numeral Converter
The Roman Numeral Converter is designed to give you an accurate answer in seconds. Follow these steps:
- 1Choose conversion direction: Integer to Roman or Roman to Integer
- 2Enter the number (1–3999) or Roman numeral in the input field
- 3Click Convert to see the result with step-by-step breakdown
- 4Press Enter as a shortcut to convert without clicking the button
No account or sign-up required. All calculations run locally in your browser — nothing is stored or transmitted to any server.
How It Works
Roman numerals use seven symbols: I (1), V (5), X (10), L (50), C (100), D (500), M (1000). The conversion uses subtractive notation: when a smaller value symbol appears before a larger one, it is subtracted rather than added. The six subtractive pairs are: IV (4), IX (9), XL (40), XC (90), CD (400), CM (900). Integer to Roman: work through a lookup table from largest to smallest (M, CM, D, CD, C, XC, L, XL, X, IX, V, IV, I), greedily subtracting values and appending the corresponding symbols. Roman to Integer: scan left to right; if the current symbol is smaller than the next symbol, subtract it — otherwise add it. MCMXCIX: M(1000) + CM(900) + XC(90) + IX(9) = 1999.
Frequently Asked Questions
What are the Roman numerals 1 to 10?
I (1), II (2), III (3), IV (4), V (5), VI (6), VII (7), VIII (8), IX (9), X (10). The subtractive forms IV (4) and IX (9) are key — placing I before V or X means subtract rather than add. Beyond 10: XX (20), XXX (30), XL (40), L (50), XC (90), C (100), D (500), M (1000).
Why can Roman numerals only go up to 3,999?
The standard Roman numeral system uses M (1000) as its largest symbol. The maximum is MMMCMXCIX (3,999) because you can only use three consecutive M's before the system breaks its own rules. Ancient Romans extended the system by placing a bar (vinculum) over numerals to multiply by 1,000, allowing numbers up to 3,999,000 — but this extended notation is not standardised in modern use.
What year is MMXXIV in Roman numerals?
MMXXIV = 2024. Breaking it down: MM = 2000, XX = 20, IV = 4. Total: 2024. Movie and TV production years are traditionally displayed in Roman numerals in end credits. MMXXV = 2025, MMXXVI = 2026. Enter any year between 1 and 3999 in this converter to get the Roman numeral form instantly.
How do subtractive pairs work in Roman numerals?
When a smaller value symbol appears immediately before a larger one, it is subtracted from the larger. The six valid subtractive pairs are: IV (5−1=4), IX (10−1=9), XL (50−10=40), XC (100−10=90), CD (500−100=400), CM (1000−100=900). Only these specific pairs are valid — you cannot write IC for 99 (must be XCIX) or VX for 5 (not a standard form).
Is the Roman numeral converter free?
Yes — completely free with no sign-up needed. Converts any integer 1–3999 to Roman numerals and any valid Roman numeral back to an integer. Shows conversion steps for learning. All conversions run in your browser instantly.