Roman Numeral Converter
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Roman Numeral Converter
Convert from Arabic to Roman and back (1 to 3999)
Table of Roman symbols
| Symbol | Value |
|---|---|
| I | 1 |
| V | 5 |
| X | 10 |
| L | 50 |
| C | 100 |
| D | 500 |
| M | 1000 |
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Roman numeral converter: Arabic ↔ Roman
This free tool converts Roman numerals to Arabic numbers and back, from 1 to 3999, the range covered by standard Roman notation. Choose the conversion direction, type the value and press Convert: the result is instant, with no sign-up.
The rules of Roman numerals
Roman numerals use seven symbols, each with a fixed value:
| Symbol | I | V | X | L | C | D | M |
|---|---|---|---|---|---|---|---|
| Value | 1 | 5 | 10 | 50 | 100 | 500 | 1000 |
The overall value is obtained by combining the symbols according to two rules:
- Additive rule: symbols of equal or decreasing value are added from left to right. Example: XVII = 10 + 5 + 1 + 1 = 17.
- Subtractive rule: a symbol of lower value placed before a higher one is subtracted. The only allowed combinations are IV (4), IX (9), XL (40), XC (90), CD (400), CM (900).
- The same symbol is not repeated more than three times in a row (this is why 4 is written IV and not IIII).
- The symbols V, L and D are never repeated and are never used for subtraction.
Conversion examples
| Arabic | Roman |
|---|---|
| 4 | IV |
| 9 | IX |
| 49 | XLIX |
| 99 | XCIX |
| 2024 | MMXXIV |
| 2026 | MMXXVI |
| 1984 | MCMLXXXIV |
| 3999 | MMMCMXCIX |
What Roman numerals are used for today
Although they are no longer used for calculations, Roman numerals remain common in many contexts: clock faces, the numbering of centuries and chapters, the names of popes and monarchs (e.g. Louis XIV), dates carved on monuments and film end credits. Knowing how to read and write them correctly is useful for students, history enthusiasts and anyone who comes across these figures in everyday life.
Frequently asked questions
Why is the number 4 written IV and not IIII?
Because the standard notation does not allow more than three identical symbols in a row. For 4 you therefore use the subtractive rule (5 − 1 = IV). The form IIII appears only on some clock faces for aesthetic tradition, but it is not the standard.
What is the largest Roman numeral I can write?
With standard symbols the maximum is 3999 (MMMCMXCIX), because M is not repeated more than three times. For larger numbers the Romans used a bar above the symbol (vinculum) that multiplied its value by 1000, a notation not used in this converter.
Does zero exist in Roman numerals?
No. The Roman system has no symbol for zero, which is why conversion starts from 1.
How do I calculate a grade average or other numbers?
For schoolwork you can use the weighted average calculator, the least common multiple calculator or the percentage calculator.
