Roman Numeral Converter
Convert numbers to Roman numerals and back instantly, with a breakdown of every symbol.
Type a number or a Roman numeral — the other box converts as you type.
Roman numeral chart
| Symbol | Value | Symbol | Value |
|---|---|---|---|
| I | 1 | C | 100 |
| IV | 4 | CD | 400 |
| V | 5 | D | 500 |
| IX | 9 | CM | 900 |
| X | 10 | M | 1000 |
| XL | 40 | MM | 2000 |
| L | 50 | MMM | 3000 |
| XC | 90 | MMMCMXCIX | 3999 |
How it works
Type a number in the left box to convert it to Roman numerals, or type a Roman numeral in the right box to convert it back to a number — both directions update instantly as you type. The converter uses the standard subtractive notation (4 is IV, not IIII; 900 is CM), builds each result from the largest value down, and shows the breakdown so you can see exactly how the numeral is put together. Classic Roman numerals cover 1 to 3999, because there is no plain symbol for 5000 and the Romans had no zero. Everything is calculated in your browser with JavaScript — nothing is uploaded, and there are no ads or sign-ups.
Frequently asked questions
How do you write 2024 in Roman numerals?
2024 is MMXXIV: MM is 2000, XX is 20 and IV is 4. Type 2024 in the number box and the converter builds the numeral and shows that breakdown instantly.
What is XLII in numbers?
XLII is 42. XL is 40 (10 subtracted from 50) and II is 2. Paste any numeral — upper or lower case — into the Roman box to get the number straight away.
Why do Roman numerals stop at 3999?
Standard Roman numerals only have symbols up to M (1000), and no more than three M's are written in a row, so 3999 (MMMCMXCIX) is the highest value. There is also no symbol for zero.