Standard Roman numerals run from I (1) to MMMCMXCIX (3999). Converted entirely in your browser.
Convert numbers to Roman numerals and back, free. Roman numerals represent numbers with seven letters — I, V, X, L, C, D and M — combined by additive and subtractive rules. This converter turns Arabic numbers (1–3999) into standard Roman numerals and decodes numerals back into numbers, entirely in your browser.
It converts both directions using the standard subtractive notation (so 4 = IV, 9 = IX, 40 = XL), covering the classic 1–3999 range. 100% free, no registration, and complete privacy — everything runs locally in your browser, so your data never touches a server.
Enter a number to get its Roman numeral, or a numeral to get the number — instantly.
Uses the conventional subtractive rules (IV, IX, XL, XC, CD, CM) so output matches accepted form.
Conversion runs locally in your browser; nothing you enter is uploaded or stored.
Unlimited conversions with no account, on desktop and mobile.
Seven letters have values: I=1, V=5, X=10, L=50, C=100, D=500, M=1000. You add values left to right, except when a smaller value precedes a larger one (subtractive), e.g. IV=4, IX=9, XL=40, CM=900.
Standard Roman numerals have no symbol above M (1000), so the largest value writable with the usual letters is MMMCMXCIX = 3999. Larger numbers historically used a bar (vinculum) to multiply by 1000, which isn't part of the basic system.
No. The Roman system has no symbol for zero — the concept of zero as a number entered Western mathematics much later. Conversions therefore start at 1.
Only six: IV (4), IX (9), XL (40), XC (90), CD (400), CM (900). A smaller symbol is placed before a larger one to subtract; other combinations are written additively.
No. The conversion happens entirely in your browser; nothing you enter leaves your device.