🏛️ Roman Numerals

Romans wrote numbers as letters: I=1, V=5, X=10, L=50, C=100, D=500, M=1000, and six exceptions where a smaller letter before a bigger one subtracts — IV(4), IX(9), XL(40), XC(90), CD(400), CM(900). This page converts both ways and checks the numeral is spelled canonically: IIII reads as 4, but the tool says so instead of pretending it is how Romans wrote it.

Why there is no Roman zero

Roman numerals count things, and a counting Roman had no symbol for nothing — the word nulla (nothing) served medieval mathematicians, and the letterless gaps in their abacus did the arithmetic. That absence is why the system has no place values and never needed one: each letter simply carries its own worth, added left to right, with the subtractive pairs as an agreed shorthand. This page refuses inputs above 3999 for the same honesty reason — the overline-for-times-a-thousand convention was never one convention, and picking one silently would be inventing history.

Part of Everyday Tools. Like everything on tukuk.org: free, no account, no tracking.