Roman Numeral Converter
Roman numerals still show up on clocks, in film credits, for numbering chapters and on buildings. Enter a number between 1 and 3999 and this calculator instantly converts it to the correct Roman form, built according to the classic subtractive rules.
結果
MCMXCIV
Roman numeral
公式
Subtract the largest symbols first, smallest last
Roman numerals use seven base symbols: I=1, V=5, X=10, L=50, C=100, D=500, M=1000. The number is built by repeatedly subtracting the largest possible symbol, where combinations like IV (4) and IX (9) place a smaller symbol before a larger one to indicate subtraction.
ステップ解説
- 1Enter a whole number between 1 and 3999.
- 2The calculator repeatedly subtracts the largest possible symbol, from M down to I.
- 3Read off the complete Roman numeral as the result.
計算例
The year 1994
→ MCMXCIV (1000 + 900 + 90 + 4).
The number 44
→ XLIV (50 − 10 + 5 − 1).
The maximum: 3999
→ MMMCMXCIX (3000 + 900 + 90 + 9), the highest number that can be written with standard symbols.
Reference table
| Symbol | Value | Example combination |
|---|---|---|
| I | 1 | IV = 4 |
| V | 5 | VIII = 8 |
| X | 10 | XL = 40 |
| L | 50 | LX = 60 |
| C | 100 | CM = 900 |
| D | 500 | DC = 600 |
| M | 1000 | MM = 2000 |
The seven base symbols; every Roman numeral between 1 and 3999 is built from these.
よくある間違い
- Assuming any symbol can repeat indefinitely; IIII for 4 is wrong, IV is correct.
- Repeating a symbol more than three times in a row, such as XXXX instead of XL for 40.
- Combining two subtractive symbols that isn't allowed, such as IL for 49 instead of XLIX.
活用シーン
- Looking up a year or chapter number in Roman numerals.
- Composing an engraving text for a watch, ring or monument.
- Recognizing the episode or season number of a show written in Roman numerals.
よくある質問
Why does this stop at 3999?
With the standard symbols you cannot write higher than 3999 without extra notation (such as a bar over a letter, which multiplies its value by 1000).
Is there a Roman symbol for zero?
No, the classical Roman numeral system had no separate symbol for zero; the concept was sometimes described with the Latin word "nulla" instead of a digit.
How do I read a long Roman numeral like MMMCMXCIX?
Split it into blocks: MMM=3000, CM=900, XC=90, IX=9. Add the blocks together and you get 3999. Always work left to right, from the largest value to the smallest.
Are Roman numerals still officially used?
Yes, among other things for numbering Olympic Games, Super Bowls, monarchs (such as Queen Elizabeth II) and film sequels, and on clock faces and copyright years in film credits.
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