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Roman Numeral Converter

Type a number from 1 to 3,999 to get its Roman numeral, or type a numeral to get the number, with each part's value shown so you can check the working. 2026 is MMXXVI and 1994 is MCMXCIV. Non-standard numerals such as IIII are read and the standard spelling suggested. Everything runs in your browser.

Runs entirely in your browser

Updated

How to use the Roman Numeral Converter

  1. 1Type a number in the Number box, or a numeral in the Roman numeral box.
  2. 2Read the result in the other box — both update as you type.
  3. 3Check “How it adds up” to see the value of each part.
  4. 4Copy the numeral with the copy button.

How it works

Roman numerals use seven letters: I = 1, V = 5, X = 10, L = 50, C = 100, D = 500 and M = 1,000. Values are added from left to right, except that a smaller numeral before a larger one is subtracted.

Standard form allows only six subtractive pairs: IV (4), IX (9), XL (40), XC (90), CD (400) and CM (900), and no letter repeats more than three times. That is why 4 is IV, 1999 is MCMXCIX and not MIM, and 3,999 (MMMCMXCIX) is the largest number written this way.

Numbers are converted by taking the largest value that fits — 1,000, 900, 500, 400 and so on down to 1 — as many times as it fits. Numerals are read by adding each letter's value, subtracting it when the next letter is larger.

Older and decorative numerals sometimes use other forms, such as IIII on clock faces. Those are read as intended and the standard spelling is suggested, so you can choose which to use.

Worked example

Writing 1994

  1. 1,000 → M
  2. 900 → CM
  3. 90 → XC
  4. 4 → IV

Result: MCMXCIV

Tips and common mistakes

  • Check film and book copyright years by pasting the numeral in.
  • For tattoos and engravings, double-check the standard form and the date order before committing.
  • Use upper case for formal writing; lower case (iv, ix) is common for page numbers in prefaces.
  • Remember that no symbol repeats more than three times in standard form.

Frequently asked questions

What is the largest Roman numeral?
In standard form, 3,999 (MMMCMXCIX). Larger numbers were written with a bar over a numeral to multiply it by 1,000, which has no standard keyboard form.
Is there a Roman numeral for zero?
No. The Romans had no numeral for zero; the word nulla was sometimes used.
Why do clocks show IIII instead of IV?
It is a long-standing clock-making tradition, often said to balance the dial visually. IV is the standard form, but both are read as 4.
How do I write a year such as 2026?
2026 is MM (2,000) + XX (20) + VI (6) = MMXXVI. Type any year from 1 to 3,999 to convert it.
Can I type lower-case numerals?
Yes. Lower case is accepted and converted to capitals.
Is anything sent to a server?
No. The conversion runs in your browser.
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