What is Roman Numeral Converter?
A Roman numeral converter moves between Arabic numbers and the Roman letters I, V, X, L, C, D and M. Those letters are added together, and a smaller letter placed before a larger one is taken away instead, which is how IV gives 4 and IX gives 9. Plain letters reach 3,999, so higher values are written with the vinculum overline.
Quick answers
Common numbers with the numeral that represents them, and how each one is built. An overline multiplies the letters it covers by 1,000, which is how values from 4,000 up are written.
| Number | Roman numeral | Built from |
|---|---|---|
| 4 | IV | 5 minus 1 |
| 9 | IX | 10 minus 1 |
| 40 | XL | 50 minus 10 |
| 90 | XC | 100 minus 10 |
| 400 | CD | 500 minus 100 |
| 900 | CM | 1,000 minus 100 |
| 1,999 | MCMXCIX | 1,000 + 900 + 90 + 9 |
| 2,024 | MMXXIV | 2,000 + 20 + 4 |
| 2,025 | MMXXV | 2,000 + 20 + 5 |
| 3,999 | MMMCMXCIX | 3,000 + 900 + 90 + 9 |
| 4,000 | I̅V̅ | 4 × 1,000 |
Best for
- Naming chapters, events, and editions
- Reading clock faces and copyright dates
- Homework and quick lookups
- Converting years and large numbers to Roman numerals
Privacy
Everything is converted locally in your browser. No input is stored or sent anywhere.
Quick tips
- Invalid sequences like "IIII" are rejected so you always get a valid result.
- Only I, X, C and M may repeat, and only three times, which is why 4,000 cannot be written as MMMM.
- The reference table below is a lookup list, not a limit. Type any number up to 3,999,999 into the converter to go further.
How to use this tool
- Enter a number between 1 and 3,999,999 to get its Roman numeral.
- Or type or paste a Roman numeral to get its value. Overline marks are parsed too.
- Check the reference table below when you only need one common value instead of a conversion.
- Copy whichever result you need.
Common questions
How do you write 3,999,999 in Roman numerals?
3,999,999 in Roman numerals is MMMCMXCIX with an overline (vinculum) over each letter of the first group, followed by CMXCIX. The overline multiplies those symbols by 1,000: 3,999 × 1,000 + 999 = 3,999,999.
What is the largest number Roman numerals can express?
With vinculum notation this converter supports up to 3,999,999. Without overlines, standard Roman numerals stop at 3,999 (MMMCMXCIX) because no single letter exceeds 1,000.
What is 3999 in Roman numerals?
3999 in Roman numerals is MMMCMXCIX, the largest number that can be written with standard letters only. One more (4000) requires the vinculum: IV with an overline.
Is there a year zero?
No. Roman numerals have no symbol for zero, so the smallest supported value is 1.
What are the Roman numeral symbols?
Roman numerals use seven letters: I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1000. Numbers are formed by combining these letters additively, with subtractive notation for values like 4 (IV) and 9 (IX).
Can I convert years to Roman numerals?
Yes. Any year from 1 to 3999 can be written with standard letters. For example, 2024 = MMXXIV, 1999 = MCMXCIX, 2025 = MMXXV.
Are invalid Roman numerals rejected?
Yes. The converter validates input and rejects invalid sequences like IIII or IC, so you always get a correct result.