Roman Numeral Converter
Type a number from 1 to 3999 and get its Roman numeral — or paste a Roman numeral and get the number back. Both directions run instantly in your browser, in strict standard notation (IV, IX, XL, XC, CD, CM), and the converter shows its working step by step so you can check it before anything gets engraved, printed or inked.
Strict mode: only the standard form is accepted. IIII, VX, IL or DD get flagged with the exact character where the numeral goes wrong, plus the correct form.
How the conversion works
Roman numerals are built from seven letters — I (1), V (5), X (10), L (50), C (100), D (500) and M (1000) — written largest first and added up. Six pairs break that rule on purpose: a smaller letter placed before a larger one subtracts instead, giving IV (4), IX (9), XL (40), XC (90), CD (400) and CM (900). Those six pairs are the whole secret to reading and writing standard numerals, and they are why 1999 is MCMXCIX rather than a long string of I's.
Here is 2449 taken apart the same way the converter above does it:
- MM2,000 — 2 × M (1,000)
- CD400 — 1 × CD (400)
- XL40 — 1 × XL (40)
- IX9 — 1 × IX (9)
- MMCDXLIX2449 in total
Quick reference
| Number | Roman |
|---|---|
| 1 | I |
| 4 | IV |
| 9 | IX |
| 14 | XIV |
| 40 | XL |
| 44 | XLIV |
| 90 | XC |
| 99 | XCIX |
| 400 | CD |
| 500 | D |
| 944 | CMXLIV |
| 1,999 | MCMXCIX |
| 2,026 | MMXXVI |
| 2,449 | MMCDXLIX |
| 3,999 | MMMCMXCIX |
Need the full table? The chart of Roman numerals 1–100 lists every number in the first hundred, and Roman numerals 1 to 1000 covers the hundreds in anchor tables. Writing a year — for a tattoo, a cornerstone or a bookplate? The year pages convert every year from 1950 to 2029.
The range, honestly stated
Standard Roman notation covers 1 to 3999 (MMMCMXCIX). There is no zero, and no standard symbol beyond M — historical systems drew a line over a numeral to multiply it by 1000, but that convention is not part of the standard form used today, so this converter stops at 3999 and tells you so instead of inventing notation. If you type something above the range, you will get a clear message rather than a made-up answer.
Converting a date instead?
Birthdays, wedding dates and anniversaries are the most common thing people convert — usually for a tattoo, a ring engraving or a piece of jewellery. The Roman numeral date converter handles the day, month and year as one date, in either month·day·year or day·month·year order, and includes a checklist for double-checking the result before you commit to it.
Frequently asked questions
What is 2026 in Roman numerals?
MMXXVI — MM (2000) + XX (20) + VI (6). Try it in the converter above.
Why is IIII rejected? Clock faces use it.
Many clock faces do use IIII for tradition and symmetry, but the standard written form of 4 is IV. This converter follows the standard form everywhere, so IIII is flagged and IV is suggested — that consistency matters when a numeral is going on paper, stone or skin.
Can a Roman numeral be bigger than 3999?
Not in standard notation: M (1000) may repeat at most three times. Medieval and later writers sometimes used an overline (vinculum) to multiply by 1000, but it is not standard today, so we cap the range at 3999 and say so openly.
How do I write a date in Roman numerals?
Convert the day, month and year separately and join them with a separator, e.g. March 14, 2025 becomes III · XIV · MMXXV in month·day·year order. The date converter does this in one step, in either order.
Is the converter strict about letter order?
Yes, in the Roman → Number direction. A string like VX or IC uses a subtraction pair that standard notation does not allow; the tool points at the exact character where it breaks and shows the correct form of the value.