🏛️ Roman Numeral Converter
Convert numbers to Roman numerals and Roman numerals to numbers, with each symbol broken down step by step.
Quick answer: Write the number using the largest symbols first, using subtractive pairs for 4s and 9s. 1999 is MCMXCIX (M = 1000, CM = 900, XC = 90, IX = 9), and MMXXVI is 2026.
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Roman Numeral Converter inputs
Result
1999 in Roman numerals
MCMXCIX
| M | 1000 |
| CM | 900 |
| XC | 90 |
| IX | 9 |
| Total | 1000 + 900 + 90 + 9 = 1999 |
Roman numeral symbols
| Symbol | Value | Subtractive pair | Value |
|---|---|---|---|
| I | 1 | IV | 4 |
| V | 5 | IX | 9 |
| X | 10 | XL | 40 |
| L | 50 | XC | 90 |
| C | 100 | CD | 400 |
| D | 500 | CM | 900 |
| M | 1000 |
How Roman numerals work
Roman numerals use seven letters: I = 1, V = 5, X = 10, L = 50, C = 100, D = 500 and M = 1,000. Symbols are written from largest to smallest and added together. When a smaller symbol comes before a larger one it is subtracted, which gives the six pairs IV, IX, XL, XC, CD and CM.
Number → numeral: repeatedly take the largest value from M, CM, D, CD, C, XC, L, XL, X, IX, V, IV, I that fits
Worked example: 1999
- 1999 − 1000 = 999 → M
- 999 − 900 = 99 → CM
- 99 − 90 = 9 → XC
- 9 − 9 = 0 → IX
Result: MCMXCIX. Reading it back, M + CM + XC + IX = 1000 + 900 + 90 + 9 = 1999.
Common numerals
| Number | Numeral | Number | Numeral |
|---|---|---|---|
| 4 | IV | 90 | XC |
| 9 | IX | 400 | CD |
| 14 | XIV | 500 | D |
| 40 | XL | 2000 | MM |
| 49 | XLIX | 2026 | MMXXVI |
Reading a numeral
Work left to right. If a symbol is smaller than the one after it, subtract it; otherwise add it. In MCMXCIX, M adds 1000, C before M subtracts 100, M adds 1000, X before C subtracts 10, and so on, giving 1999.
Tips
- Validity check: I, X, C and M may repeat up to three times; V, L and D never repeat.
- Years on films and buildings are easiest read in chunks: MCM-LXXX-IV = 1900 + 80 + 4 = 1984.
- Lowercase numerals (xiv) are fine – the converter reads them the same way.
Frequently asked questions
Why is 4 written IV and not IIII?
Standard Roman numerals never repeat a symbol four times. Instead a smaller symbol placed before a larger one is subtracted: IV = 5 − 1 = 4 and IX = 10 − 1 = 9. (Some clock faces still use IIII by tradition.)
What is the largest number in Roman numerals?
With the standard symbols the largest is 3,999 – MMMCMXCIX. Larger numbers used a bar over a numeral to multiply it by 1,000, which is not part of the standard form.
Is there a Roman numeral for zero?
No. The Roman system had no symbol for zero; medieval scholars sometimes wrote "nulla" (N). Converters therefore start at 1.
Which subtractive pairs are allowed?
Only six: IV (4), IX (9), XL (40), XC (90), CD (400) and CM (900). Forms like IL for 49 or IC for 99 are not valid – 49 is XLIX and 99 is XCIX.