Roman Numerals Calculator
Convert between Roman numerals and decimal numbers
Roman Numerals Calculator
Convert between Roman numerals and decimal numbers with our comprehensive calculator.
12 = 20 + 1
10 = X
2 = II
12 = XII
Roman Numerals Chart
| Roman | Decimal |
|---|---|
| I | 1 |
| V | 5 |
| X | 10 |
| L | 50 |
| C | 100 |
| D | 500 |
| M | 1000 |
Roman Numeral Rules
- Symbols are combined to add their values: XVI = 10 + 5 + 1 = 16
- When a smaller symbol appears before a larger one, subtract the smaller value: IV = 5 - 1 = 4
- A symbol cannot be repeated more than three times consecutively: III is valid, IIII is not
- Symbols V, L, and D cannot be repeated or used in subtractive notation
- Only I can be used before V and X, only X before L and C, and only C before D and M
- The largest number that can be represented in standard notation is 3,999 (MMMCMXCIX)
Common Roman Numeral Numbers
Roman Numerals: History & Applications
"Medieval monks were the ones who standardized the use of lowercase Roman numerals."
History of Roman Numerals
Origins (~ 800 BCE)
Roman numerals evolved from Etruscan numerals, which were themselves derived from Greek numerals. The earliest known examples date back to around 800 BCE.
Roman Republic and Empire (509 BCE - 476 CE)
During this period, Roman numerals were the standard numbering system throughout the Roman territories. They were used for trade, taxation, and record-keeping.
Medieval Period (5th - 15th century)
Roman numerals continued to be widely used throughout Europe. Medieval manuscripts and early printed books used them for chapter numbers and pagination.
Renaissance to Modern Day
With the introduction of Arabic numerals in Europe around the 12th century, Roman numerals gradually declined in everyday use but remained important for specific applications.
Did You Know?
- The subtractive principle (IV instead of IIII) wasn't standardized until the Middle Ages.
- On clock faces with Roman numerals, IIII is often used instead of IV for aesthetic balance.
- Romans would have written the year 2023 as MMXXIII.
- Romans performed calculations using an abacus, not with their numeral system.