Convert between Roman numerals (I, V, X, L, C, D, M) and Arabic numbers. Supports values from 1 to 3,999. Click any reference value to load it instantly.
→ Arabic → Roman
Arabic number (1–3999)
Enter a number above
← Roman → Arabic
Roman numeral (e.g. MMXXIV)
Enter a Roman numeral above
Quick Reference — click to load
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How to use
Type an Arabic number on the left or a Roman numeral on the right.
The conversion happens instantly with full validation.
Click any reference value to load it, then copy the result.
FAQ
Classic Roman numerals from 1 (I) to 3999 (MMMCMXCIX). Larger numbers traditionally used overlines which aren't widely supported in plain text.
Input is checked against the canonical Roman numeral grammar (no repeats of V, L, or D; M/C/X/I repeat up to 3; valid subtractive pairs CM/CD/XC/XL/IX/IV).