Units & Numbers Tools
Roman Numeral Converter
Convert between numbers and Roman numerals.
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What is Roman Numerals?
A bidirectional Roman numeral converter following the standard subtractive notation (IV, IX, XL, XC, CD, CM).
How it works
To Roman: greedily subtract the largest fitting numeral value. From Roman: walk left-to-right, adding values and subtracting when a smaller numeral precedes a larger one.
- Enter your input. Type or paste your input into the field above — the tool responds instantly.
- Review the result. Output updates live as you type. Everything runs entirely in your browser.
- Copy or download. Use the Copy button to grab the result, or Download to save it as a file.
Examples
Realistic sample
Paste or type any realistic input — the tool computes the result locally and instantly.
Common mistakes
Expecting a server round-trip
Nothing is uploaded — every tool in this category runs entirely in your browser.