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Converts between Arabic numbers and Roman numerals with validation. Use for chapters, clocks or outlines; differs from base-converter by Roman symbols vs positional bases. Returns numeral or number. 100% client-side.
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Converts between Roman numerals and integers in both directions. Enter a number (1–3999) to get its Roman numeral representation, or enter a Roman numeral to get its numeric value. Supports standard subtractive notation like IV for 4 and IX for 9.
Roman numerals appear in book chapters, movie copyright dates, Super Bowl numbering, and clock faces. Quickly converting between Roman and Arabic numerals saves manual calculation and avoids errors with subtractive notation.
This tool is part of the DevStackIO platform — a collection of free online developer tools from DevStackIO. Browse more free developer resources on DevStackIO.
Students learning Roman numerals, editors formatting chapter numbers, developers working with legacy numbering systems, and anyone encountering Roman numerals in everyday life.
Select the conversion direction: Number to Roman or Roman to Number
Enter your value in the input field
The converted result appears instantly in the output area
Click Copy to copy the result to your clipboard
Use uppercase letters for Roman numeral input (I, V, X, L, C, D, M)
Switch direction to double-check the result
1984 → MCMLXXXIVMMXXIV → 2024XLII → 424 → IV1776 → MDCCLXXVIMCMXCIX → 19992025 → MMXXVWhat is the range of supported numbers?
1 to 3999, the standard range for Roman numerals.
Does it handle subtractive notation like IV and IX?
Yes, both output and input use standard subtractive notation.
Can I convert numbers larger than 3999?
Not in standard Roman numerals; the tool enforces the traditional limit.
Is my data shared?
No, the conversion runs locally in your browser.
Why is 4 written IV instead of IIII?
Subtractive notation places a smaller numeral before a larger one to indicate subtraction, which is the modern standard.
How do I write the current year in Roman numerals?
2025 is MMXXV (M=1000, M=1000, XX=20, V=5).
Authoritative specifications, standards, and in-depth reading for Roman Numeral Converter.
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