Overview
What this converter does
Convert any number from 1 to 3,999 into Roman numerals, and convert Roman numerals back into ordinary numbers. The tool validates your input, shows how each numeral breaks down into its value, and includes a reference chart. It runs entirely in your browser.
The building blocks
The seven Roman numerals
Roman numerals use seven letters, each with a fixed value:
| Value | Memory aid | |
|---|---|---|
| I | 1 | like a single tally mark |
| V | 5 | an open hand (five fingers) |
| X | 10 | two hands crossed |
| L | 50 | — |
| C | 100 | C for centum (Latin: hundred) |
| D | 500 | — |
| M | 1000 | M for mille (Latin: thousand) |
How numbers are built
The rules
Addition (largest first)
Write numerals from largest to smallest, left to right, and add them up. VIII = 5 + 1 + 1 + 1 = 8. LXVII = 50 + 10 + 5 + 1 + 1 = 67.
Subtraction (smaller before larger)
When a smaller numeral comes directly before a larger one, you subtract it. There are exactly six valid subtractive pairs:
- IV = 4 (5 − 1)
- IX = 9 (10 − 1)
- XL = 40 (50 − 10)
- XC = 90 (100 − 10)
- CD = 400 (500 − 100)
- CM = 900 (1000 − 100)
The repetition limit
A numeral can repeat at most three times in a row. That's why 4 is IV, not IIII, and 40 is XL, not XXXX. V, L, and D are never repeated at all.
Quick reference
Common conversions
| Roman | How it breaks down | |
|---|---|---|
| 4 | IV | 5 − 1 |
| 9 | IX | 10 − 1 |
| 14 | XIV | 10 + (5 − 1) |
| 40 | XL | 50 − 10 |
| 90 | XC | 100 − 10 |
| 100 | C | 100 |
| 500 | D | 500 |
| 2024 | MMXXIV | 1000 + 1000 + 10 + 10 + (5 − 1) |
| 2026 | MMXXVI | 1000 + 1000 + 10 + 10 + 5 + 1 |
| 3999 | MMMCMXCIX | the maximum standard value |
Everyday sightings
Where Roman numerals are still used
- Clock and watch faces (often with IIII for 4)
- Movie and TV copyright years in the credits
- Super Bowl numbering (Super Bowl LVIII)
- Book chapters, outlines, and appendices
- Monarch and pope names (Elizabeth II, Pope Francis is not numbered, but Benedict XVI was)
- Building cornerstones and monument dates
Behind the scenes
Privacy and how it runs
Runs in your browser
Common questions
What is 2026 in Roman numerals?
MMXXVI: M (1000) + M (1000) + X (10) + X (10) + V (5) + I (1).
Why is there no zero in Roman numerals?
The Roman system had no symbol for zero — it was a positional concept that came later from Indian and Arabic mathematics. The smallest Roman numeral is I (1).
How high can Roman numerals go?
With the standard seven letters, the maximum is 3,999 (MMMCMXCIX). Larger numbers historically used a bar (vinculum) over a numeral to multiply it by 1,000, but that's outside the standard set this tool uses.
Is IIII ever correct for 4?
Not in the standard system — 4 is IV. But many clock faces use IIII for visual balance with the VIII on the opposite side. It's a traditional exception, not a rule.
How do I write my birth year?
Type the year into the number field. For example, 1995 becomes MCMXCV, and the breakdown shows M (1000) + CM (900) + XC (90) + V (5).