What is vinculum notation?

Vinculum (or bar) notation places a horizontal bar over a Roman numeral to multiply its value by 1,000. For example, V̄ = 5,000 and M̄ = 1,000,000. This extends the standard system beyond 3,999.

What is the maximum number this tool supports?

This tool supports values up to 4,999,999 using vinculum notation. Standard Roman numerals without vinculum only go up to 3,999.

Is IV the only way to write 4?

The standard subtractive notation uses IV for 4, IX for 9, XL for 40, XC for 90, CD for 400, and CM for 900. Some historical texts used IIII for 4, but this tool follows the modern standard.

What is the difference from the basic Roman numeral tool?

This advanced version adds vinculum (over-bar) notation for numbers above 3,999, bidirectional input, conversion history, and a complete symbol reference table.

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Roman Numeral Converter (Advanced)

Convert between Roman numerals and decimals with vinculum support

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Bidirectional converter for Roman numerals and decimal numbers supporting values up to 4,999,999 using vinculum notation (a bar over a numeral multiplies it by 1,000). Type a decimal to get the Roman numeral or type Roman numerals to get the decimal value. A history of your last 10 conversions is saved locally, and a full reference table of all Roman symbols and their values is always visible below.

使い方

1 Type a decimal number (1–4,999,999) in the left field to convert to Roman numerals.
2 Or type Roman numeral characters in the right field to convert to decimal.
3 Numbers above 3,999 use vinculum notation shown with an overline.
4 Review the full symbol table at the bottom for a quick reference guide.

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