Roman Numeral Converter — Number ↔ Roman
Two-way Roman numeral converter (1–3999) with full validation. Client-side.
Number → Roman
Roman → Number
How to use
- 1 Type a number (1–3999) to get its Roman numeral.
- 2 Or type a Roman numeral to get the number.
- 3 Invalid numerals (like IIII or VX) are rejected.
Why use this tool
- Two-way conversion with full validation of Roman numeral rules.
- Covers the standard range 1 to 3999 (I to MMMCMXCIX).
- Runs entirely in your browser.
Frequently asked questions
What are the Roman numeral symbols?
I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1000. Smaller values before larger ones are subtracted (IV = 4, IX = 9).
Why is the maximum 3999?
Standard Roman numerals only go up to 3999 (MMMCMXCIX); larger numbers historically used a bar (vinculum) for ×1000, which is rarely used today.
Why is IIII invalid?
A symbol may repeat at most three times; 4 is written IV (subtractive notation), not IIII.
Is there a zero in Roman numerals?
No — the Roman system has no symbol for zero.
What is Roman Numeral Converter?
A Roman numeral converter translates between Arabic numbers and Roman numerals (I, V, X, L, C, D, M), using subtractive notation and validating the standard 1–3999 range.
Roman Numeral Converter is a free math utility by Zerethon Tools. Two-way Roman numeral converter (1–3999) with full validation. Client-side. Runs entirely in the browser — no signup, no upload.
- Category
- Math
- Pricing
- Free
- Privacy
- Browser-based
- Signup
- Not required
Privacy
Your data never leaves your browser unless explicitly stated. Roman Numeral Converter runs entirely client-side — no server upload, no logging, no tracking of your input.
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