Number to Roman Numerals Converter
Convert between Arabic integers and Roman numerals (I, V, X, L, C, D, M): numbers → Roman and Roman → numbers, full standard range 1–3999, strict rule validation with instant error hints, recent 10 records saved locally, one-click copy and PNG download.
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What is it
This tool converts Arabic integers into standard Roman numerals and restores a number from Roman numerals. Roman numerals use seven letters — I, V, X, L, C, D and M for 1, 5, 10, 50, 100, 500 and 1000 — with the subtractive rule: IV is 4, IX is 9, XL is 40 and CM is 900. It covers the full standard range 1–3999, validates every symbol strictly and shows an instant hint when the input is written incorrectly.
Notes & fun facts
Roman numerals were born in ancient Rome for counting and bookkeeping, then spread to clock faces, chapter numbers, royal titles and monument inscriptions. With no symbol for zero, they express values through letter combinations — still in use after more than two thousand years.
Origin & history
Roman numeral rules evolved over centuries: early inscriptions used the additive IIII for 4, and the subtractive forms (IV, IX) became standard later. Clock faces still show IIII today, while formal documents prefer IV.
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