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Numio

Roman Numeral Converter

Convert integers from 1 to 3999 into Roman numerals, or decode canonical Roman notation back to decimal.

Mode

Input

Result

Type or paste on the left — the result updates as you type.

Uses subtractive forms such as IV and IX. Zero, negative numbers, overbars and noncanonical forms such as IIII are rejected.

Up to 100,000 UTF-16 units per input and 1,000,000 per result. See the supported formats and examples below.

Format references

Tool page updated: